Installation and servicing of air-conditioning equipment can
be hazardous due to system pressure and electrical components. Only trained and qualified service personnel should
install, repair, or service air-conditioning equipment. Untrained
personnel can perform the basic maintenance functions of
replacing filters. Trained service personnel should perform all
other operations.
When working on air-conditioning equipment, observe precautions in the literature, tags and labels attached to the unit,
and other safety precautions that may apply. Follow all safety
codes. Wear safety glasses and work gloves. Use quenching
cloth for unbrazing operations. Have fire extinguishers available for all brazing operations.
WARNING
Before performing service or maintenance operation on
unit, turn off and lock off main power switch to unit.
Electrical shock can cause personal injury and death.
Shut off all power to this equipment during installation
and service. The unit may have an internal non-fused
disconnect or a field-installed disconnect.
CAUTION
This unit uses a microprocessor-based electronic control
system. Do not use jumpers or other tools to short out com-
ponents or to bypass or otherwise depart from recommended procedures. Any short-to-ground of the control
board or accompanying wiring may destroy the electronic
modules or electrical components.
WARNING
1. Improper installation, adjustment, alteration, service,
or maintenance can cause property damage, personal
injury, or loss of life. Refer to the User’s Information
Manual provided with this unit for more details.
2. Do not store or use gasoline or other flammable
vapors and liquids in the vicinity of this or any other
appliance.
2
WARNING
DO NOT USE TORCH to remove any component. System
contains oil and refrigerant under pressure.
To remove a component, wear protective gloves and goggles and proceed as follows:
a. Shut off electrical power to unit.
b. Recover refrigerant to relieve all pressure from sys-
tem using both high-pressure and low pressure ports.
c. Traces of vapor should be displaced with nitrogen
and the work area should be well ventilated. Refrigerant in contact with an open flame produces toxic
gases.
d. Cut component connection tubing with tubing cutter
and remove component from unit. Use a pan to catch
any oil that may come out of the lines and as a gage
for how much oil to add to the system.
e. Carefully unsweat remaining tubing stubs when nec-
essary. Oil can ignite when exposed to torch flame.
Failure to follow these procedures may result in personal
injury or death.
CAUTION
DO NOT re-use compressor oil or any oil that has been
exposed to the atmosphere. Dispose of oil per local codes
and regulations. DO NOT leave refrigerant system open to
air any longer than the actual time required to service the
equipment. Seal circuits being serviced and charge with
dry nitrogen to prevent oil contamination when timely
repairs cannot be completed. Failure to follow these procedures may result in damage to equipment.
WARNING
What to do if you smell gas:
1. DO NOT try to light any appliance.
2. DO NOT touch any electrical switch, or use any
phone in your building.
3. IMMEDIATELY call your gas supplier from a neighbor’s phone. Follow the gas supplier’s instructions.
4. If you cannot reach your gas supplier call the fire
department.
GENERAL
This book contains Start-Up, Controls, Operation, Troubleshooting and Service information for the 48/50N Series rooftop
units. See Table 1. These units are equipped with ComfortLink
controls version 2.0 or higher. Use this guide in conjunction
with the separate installation instructions packaged with the
unit.
The 48/50N Series units provide ventilation, cooling, and
heating (when equipped) in variable air volume (VAV), staged
air volume (SAV™) and constant volume (CV) applications.
Table 1 — N Series Product Line
UNITSIZEAPPLICATION
48N2All
48N3All
48N4All
48N5All
48N6All
48N7All
48N8All
48N9All
50N2All
50N3All
50N4All
50N5All
50N6All
50N7All
50N8All
50N9All
LEGEND
CV — Constant Volume
SAV — Staged Air Volume
VAV — Variable Air Volume
The 48/50N units contain the factory-installed ComfortLink
control system which provides full system management. The
main base board (MBB) stores hundreds of unit configuration
settings and 8 time of day schedules. The MBB also performs
self diagnostic tests at unit start-up, monitors the operation of
the unit, and provides alarms and alert information. The system
also contains other optional boards that are connected to the
MBB through the Local Equipment Network (LEN). Information on system operation and status are sent to the MBB processor by various sensors and optional board(s) that are located
at the unit and in the conditioned space. Access to the unit controls for configuration, set point selection, schedule creation,
and service can be done via local display, using the supplied
Navigator™ device, or through the Carrier Comfort Network
(CCN) using ComfortVIEW™ software, Network Service
Tool, or other CCN device.
The ComfortLink system controls all aspects of the rooftop.
It controls the supply-fan motor, compressors, and economizer
to maintain the proper temperature conditions. The controls
also cycle condenser fans to maintain suitable head pressure.
All units are equipped with a supply fan VFD (variable frequency drive). The VAV units utilize the VFD for supply duct
pressure control. The ComfortLink controls can directly control
the speed of the VFD based on a static pressure sensor input. In
addition, the ComfortLink controls can adjust the building pressure using an optional VFD controlled power exhaust or return
fan controlled from a building pressure sensor. The control
safeties are continuously monitored to prevent the unit from operating under abnormal conditions. Sensors include pressure
transducers and thermistors. For units on CV applications, the
ComfortLink controls will direct the VFD to drive the supply
fan at low speed for low cool or heat demand and high speed on
high cool or heat demand.
®
3
A scheduling function, programmed by the user, controls
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Fig. 1 — Accessory Navigator Display
the unit occupied/unoccupied schedule. Up to 8 different
schedules can be programmed.
The controls also allow the service person to operate a service test so that all the controlled components can be checked
for proper operation.
BASIC CONTROL USAGE
ComfortLink Controls —
are a comprehensive unit-management system. The control
system is easy to access, configure, diagnose and troubleshoot.
The controls are flexible, providing constant volume and
variable air volume cooling control sequences, and heating
control sequences for two-stage electric and gas systems, modulating gas heating, SCR (silicon control rectifier) electric heat,
and hydronic heat in both Occupied and Unoccupied schedule
modes. This control also manages:
• VAV duct pressure (VAV units only), with configurable
static pressure reset
• Building pressure through four different power exhaust
schemes
• Return fan applications using fan tracking
• Condenser fan head pressure control
• Dehumidification (with optional reheat) and humidifier
sequences
• Space ventilation control, in Occupied and Unoccupied
periods, using CO
tilation defined by damper position or ventilation airflow
measurement
• Smoke control functions
• Occupancy schedules
• Occupancy or start/stop sequences based on third party
signals
• Alarm status and history and run time data
• Management of a complete unit service test sequence
• Economizer operation and Fault Diagnosis and Detection
(FDD) per California Energy Commission (CEC) Title
24-2013.
System diagnostics are enhanced by the use of sensors for
air and refrigerant temperatures and pressures. Unit-mounted
actuators provide digital feedback data to the unit control.
The ComfortLink controller is cable-ready for connection to
the Carrier Comfort Network
system. The control provides high-speed communications for
remote monitoring. Multiple 48/50N Series units can be linked
together (and to other ComfortLink controller equipped units)
using a 3-wire communication bus. The unit may be equipped
with optional BACnet communication capability.
The ComfortLink controller is also capable of communicating with a BACnet network by going through a UPC Open
controller. This permits third-party building management systems to provide remote monitoring and control of 48/50N
units. See Appendix F for additional information.
The ComfortLink control system is easy to access through
the use of a Navigator™ display. A computer is not needed to
perform unit start-up. The Navigator module provides detailed
explanations of control information.
For service flexibility, a factory-supplied Navigator™ module has an extended communication cable that can be plugged
into the unit's communication network either at the main control box or at the opposite end of the unit, at a remote modular
plug. The Navigator display provides the menu structure, control access and display data for the unit.
Navigator™ Display — The hand-held Navigator dis-
play is used with the 48/50N Series units. See Fig. 1. The Navigator display is plugged into the RJ-14 jack in the main control
box on the COMM board. The Navigator display can also be
sensors or external signals, with ven-
2
The ComfortLink controls
®
(CCN) building management
plugged into the RJ-14 jack located on the unit corner post located at the economizer end of the unit.
Operation — All units are shipped from the factory with
the Navigator display, which is located in the main control box.
See Fig. 1. The Navigator display provides the user with an interface to the ComfortLink control system. The display has arrow keys, an ESC key and an ENTER key. These keys are used
to navigate through the different levels of the display structure.
The Navigator has four lines of display. See Table 2 for the
menu structure.
The four keys are used to navigate through the display
structure, which is organized in a tiered mode structure. See
Table 2 for the first two levels of the mode structure. If the buttons have not been used for a period, the display will default to
the AUTO VIEW display category as shown under the RUN
STATUS category. To show the top-level display, press the
ESC key until a blank display is shown. Then use the and
keys to scroll through the top level categories.These are
listed in Appendix A and will be indicated on the Navigator by
the LED next to each mode listed on the face of the display.
When a specific mode or sub-mode is located, push the
ENTER key to enter the mode. Depending on the mode, there
may be additional tiers. Continue to use and keys and
the ENTER key until the desired display item is found. At any
time, the user can move back a mode level by pressing the ESC
key.
Items in the Configuration and Service Test modes are password protected. The display will prompt for a PASSWORD.
Use the ENTER and arrow keys to enter the four digits of the
password. The default password is 1111.
Pressing the ESC and ENTER keys simultaneously will display an expanded text description for each display point.
Changing item values or testing outputs is accomplished in
the same manner. Locate and display the desired item. If the
display is in rotating auto-view, press the ENTER key to stop
the display at the desired item. Press the ENTER key again so
that the item value flashes. Use the arrow keys to change the
value or state of an item and press the ENTER key to accept it.
Press the ESC key and the item, value or units display will resume. Repeat the process as required for other items.
If the user needs to force a variable, follow the same process
as when editing a configuration parameter. When using the
Navigator display, a forced variable will be displayed with a
blinking "f" following its value. For example, if supply fan requested (FA N. F ) is forced, the display shows "YESf", where
the "f" is blinking to signify a force on the point. Remove the
4
SCROLL
+
-
NAVIGATE/
EXIT
MODIFY/
SELECT
PAGE
Fig. 2 — System Pilot User Interface
force by selecting the point that is forced with the ENTER key
and then pressing both arrow keys simultaneously.
Depending on the unit model, factory-installed options and
field-installed accessories, some of the items in the various
mode categories may not apply.
Conventions Used in This Manual — This manual
will use the following conventions for discussing configuration
points for the local display (Navigator™).
Parameter names will be written with the Mode name first,
then any sub-modes, then the parameter name, each separated
by an arrow symbol (). Names will also be shown in bold
and italics. As an example, the IAQ Economizer Override Position which is located in the Configuration mode, Indoor Air
Quality Configuration sub-mode, and the Air Quality Set
Points sub-sub-mode, would be written as Configuration
IAQIAQ.SPIQ.O.P.
This path name will show the user how to navigate through
the local display structure to reach the desired configuration.
The user would scroll through the modes and sub-modes using
the UP ARROW and DOWN ARROW keys. The arrow symbol in the path name represents pressing ENTER to move into
the next level of the menu structure.
When a value is included as part of the path name, it will be
shown at the end of the path name after an equals sign. If the
value represents a configuration setting, an explanation will be
shown in parenthesis after the value. As an example, Configu-
ration
IAQAQ.CFIQ.AC = 1 (IAQ Analog Input).
Pressing the ESCAPE and ENTER keys simultaneously
will display an expanded text description of the parameter
name. The expanded description is shown in the local display
tables but will not be shown with the path names in text.
The CCN (Carrier Comfort Network
®
) point names are also
cross-referenced in the local display tables (Appendix A) for
users interface with the unit via CCN instead of the local display. The CCN tables are located in Appendix B of this
manual.
System Pilot™ Interface — The System Pilot inter-
face (33PILOT-01) is a component of the Carrier 3V™ system
and can serve as a CCN user-interface and configuration tool.
Additionally, the System Pilot interface can serve as a wallmounted temperature sensor for space temperature measurement. The occupant can use the System Pilot interface to
change set points. A security feature is provided to limit access
of features for unauthorized users. See Fig. 2 for System Pilot
interface details.
CCN Tables and Display — In addition to the Naviga-
tor display, the user can also access the same information
through the CCN tables by using the System Pilot, Service
Tool or other CCN programs. Details on the CCN tables are
summarized in Appendix B. The point names displayed in the
CCN tables and the corresponding local display acronyms
available via the Navigator display may be different and more
items are displayed in the CCN tables. As a reference, the CCN
point names are included in the local display menus shown in
Appendix A.
GENERIC STATUS DISPLAY TABLE — The GENERICS
points table allows the service/installer the ability to create a custom table in which up to 20 points from the 5 CCN categories
(Status, Config/Service-Config, Set Point, Maintenance, and Occupancy) may be collected and displayed.
In the Service-Config table section, there is a table named
"generics." This table contains placeholders for up to 20 CCN
point names and allows the user to decide which points are displayed in the GENERIC points table. Each one of these placeholders allows the input of an 8-character ASCII string.
Using a CCN method of interface, go into the Edit mode for
the Service-Config table "generics" and enter the CCN name for
each point to be displayed in the custom points table in the order
they will be displayed. When done entering point names, download the table to the rooftop unit control.
IMPORTANT: The computer system software (ComfortVIEW™, Service Tool, etc.) that is used to interact
with CCN controls always saves a template of items it
considers as static (e.g., limits, units, forcibility, 24character text strings, and point names) after the software uploads the tables from a control. Thereafter, the
software is only concerned with run time data like
value and hardware/force status. With this in mind, it
is important that anytime a change is made to the Service-Config table "generics" (which in turn changes
the points contained in the GENERIC point table), that
a complete new upload be performed. This requires
that any previous table database be completely
removed first. Failure to do this will not allow the
user to display the new points that have been created
and the software will have a different table database
than the unit control.
START-UP
IMPORTANT: Do not attempt to start unit, even
momentarily, until all items on the Start-Up Checklist
(at the back of this book) and the following steps have
been completed.
IMPORTANT: The unit is shipped with the unit control
disabled. To enable the control, set Local Machine Disable
(Service Test
Unit Preparation —
STOP) to No.
Check that unit has been installed in
accordance with the installation instructions and applicable
codes. Make sure that the economizer hoods have been installed and that the outdoor filters are properly installed.
Internal Wiring — Ensure that all electrical connections
in the control box are tightened as required. If the unit has modulating gas or SCR electric heat make sure that the LAT (leaving air temperature) sensors have been routed to the supply
ducts as required.
5
Accessory Installation — Check to make sure that all
accessories including space thermostats and sensors have been
installed and wired as required by the instructions and unit wiring diagrams.
Crankcase Heaters — Crankcase heaters are energized
as long as there is power to the unit, except when the compressors are running.
IMPORTANT: Unit power must be on for 24 hours
prior to start-up of compressors. Otherwise damage to
compressors may result.
Evaporator Fan — Fan belts and fixed pulleys are facto-
ry-installed. See Tables 3-18 for fan performance. Be sure that
fans rotate in the proper direction. Component pressure drop
data is shown in Tables 19 and 20. See Tables 21 and 22 for motor limitations.
FIELD-SUPPLIED FAN DRIVES — Supply fan and power
exhaust fan drives are fixed-pitch, non-adjustable selections, for
maximum reliability and long belt life. If the factory drive sets
must be changed to obtain other fan speeds, consult the nearest
Browning Manufacturing Co. sales office with the required new
wheel speed and the data from Physical Data and Supply Fan
Drive Data tables (center distances, motor and fan shaft diameters, motor horsepower) in Installation Instructions for a modified drive set selection. For minor speed changes, the VFD can
be used to provide speed control. See page 157 for belt installation procedure.
Controls — Use the following steps for the controls:
IMPORTANT: The unit is shipped with the unit control
disabled. To enable the control, set Local Machine Disable
(Service Test
STOP) to No.
2. Enter unit set points. The unit is shipped with the set point
default values. If a different set point is required, use the
Navigator™ display, or CCN interface to change the configuration values.
3. If the internal time schedules are going to be used, configure the Occupancy schedule.
4. Verify that the control time periods programmed meet
current requirements.
5. Use Auto Commisioning mode to verify operation of all
major components.
6. If the unit is a VAV unit make sure to configure the static
pressure set point. To check out the VFD, use the VFD instructions shipped with the unit.
Gas Heat — Verify gas pressure before turning on gas heat
as follows:
1. Turn off field-supplied manual gas stop, located external
to the unit.
2. Connect pressure gages to supply gas tap, located at fieldsupplied manual shutoff valves.
3. Connect pressure gages to manifold pressure tap on unit
gas valve.
4. Supply gas pressure must not exceed 13.5 in. wg. Check
pressure at field-supplied shut-off valve.
5. Turn on manual gas stop and initiate a heating demand.
Jumper R to W1 and R to W2 in the control box to initiate
high fire heat.
6. After the unit has run with high fire energized for several
minutes, verify that incoming pressure is 5.0 in. wg or
greater and that the manifold pressure is 3.1 in wg. If
manifold pressure must be adjusted refer to Gas Valve
Adjustment section on page 171.
7. Use the Service Test procedure to verify all heat stages of
operation.
1. Set any control configurations that are required (fieldinstalled accessories, etc.). The unit is factory configured
for all appropriate factory-installed options.
Bhp — Brake Horsepower
BkW — Brake Kilowatts
ODP — Open Drip Proof
TEFC — Total Enclosed Fan Cooled
NOMINALMAXIMUMMAXIMUM AMPS
1. Extensive motor and electrical testing on the Carrier units has
ensured that the full horsepower range of the motor can be
utilized with confidence. Using fan motors up to the horsepower
ratings shown in the Motor Limitations table will not result in
nuisance tripping or premature motor failure. Unit warranty will
not be affected.
2. All motors comply with Energy Policy Act (EPACT) Standards
effective October 24, 1997.
RATED
EFFICIENCYBHPBKWBHPBKW460 V575 V
Table 22 — Power Exhaust and Return Fan Motor Limitations
Bhp — Brake Horsepower
BkW — Brake Kilowatts
ODP — Open Drip Proof
TEFC — Total Enclosed Fan Cooled
NOMINALMAXIMUMMAXIMUM AMPS
1. Extensive motor and electrical testing on the Carrier units has
ensured that the full horsepower range of the motor can be
utilized with confidence. Using fan motors up to the horsepower
ratings shown in the Motor Limitations table will not result in
nuisance tripping or premature motor failure. Unit warranty will
not be affected.
2. All motors comply with Energy Policy Act (EPACT) Standards
effective October 24, 1997.
EFFICIENCYBHPBKWBHPBKW460 V575 V
RATED
26
CONTROLS QUICK START
The following section will provide a quick user guide to setting up and configuring the N Series units with ComfortLink
controls. See Basic Control Usage section on pages 4 and 5 for
information on operating the control.
Variable Air Volume Units Using Return Air
Sensor or Space Temperature Sensor —
configure the unit, perform the following:
1. The type of control is configured under Configuration
UNITC.TYP. Set C.TYP to 1 (VAV-RAT) for return
air sensor. Set C.TYP to 2 (VAV-SPT) for space temperature sensor.
NOTE: For VAV with a space sensor (VAV-SPT), under
Configuration
space sensor by setting SPT.S to ENBL.
NOTE: Refer to the section on static pressure control for information on how to set up the unit for the type of supply fan control desired.
2. The space temperature set points and the supply air set
points are configured under the Setpoints menu. The
heating and cooling set points must be configured. See
the Heating Control and Cooling Control sections for further description on these configurations. Configure the
following set points:
OHSPOccupied Heat Set Point
OCSPOccupied Cool Set Point
UHSPUnoccupied Heat Set Point
UCSPUnoccupied Cool Set Point
GAPHeat-cool Set Point Gap
V. C . O NVAV Occupied Cool On Delta
V. C . O FVAV Occupied Cool Off Delta
Also configure the following points in the Configuration
BP D.LV.T menu:
L.H.ON Demand Level Low Heat On
L.H.OF Demand Level Low Heat Off
3. To program time schedules, make sure SCH.N=1 under
Configuration
the control to use local schedules.
4. Under the Time Clock
sired schedule. See Time Clock section for further
descriptions of these configurations.
5. Under Configuration
Static Pressure set point should be configured.
6. If supply air temperature reset is desired, under the
Configuration
points should be configured:
RS.CFEDT Reset Configuration
RTIOReset Ratio
LIMTReset Limit
RES.SEDT 4-20 mA Reset Input
This applies to both TSTAT MULTI and SENSOR
MULTI modes.
NOTE: Configure either RTIO and LIMT or RES.S. All three
are not used.
7. See the Economizer Configurations section for additional
economizer option configurations.
8. See the Exhaust Configurations section for addition exhaust option configurations.
UNITSENSSPT.S, enable the
IAQSC.OVSCH.N to configure
SCH.L submenu, enter the de-
SP
EDT.R submenu, the following set
SP.SP, the Supply Duct
To
Multi-Stage Constant Volume and Staged Air
Volume Units with Mechanical Thermostat —
To configure the unit, perform the following:
1. Under Configuration
(TSTAT MULTI). See the Economizer Configurations
section for additional economizer option configurations.
2. Under the Setpoints menu, set the following
configurations:
SA.HISupply Air Set Point Hi
SA.LOSupply Air Set Point Lo
See the Exhaust Configurations section for additional exhaust option configurations.
UNITC.TYP, set C.TYP to 3
Multi-Stage Constant Volume and Staged Air
Volume Units with Space Sensor —
the unit, perform the following:
1. Under Configuration
(SPT MULTI).
2. Under the Setpoints menu, the following configurations
should be set:
SA.HISupply Air Set Point Hi
SA.LOSupply Air Set Point Lo
3. Under the Setpoints submenu, the heating and cooling set
points must be configured:
4. Under Configuration
the space sensor by setting SPT.S to ENBL.
5. Under Configuration
1 for continuous fan or 0 for automatic fan.
6. To program time schedules, set SCH.N=1 under Config-
uration
trol to use local schedules.
7. Under the Timeclock
sired schedule. See Time Clock section for further
descriptions of these configurations.
8. See the Economizer Configurations section for additional
economizer option configurations.
9. See the Exhaust Configurations section for additional exhaust option configurations.
Cool/Heat Set Point Offsets (located in the
Configuration menu)
IAQSC.OVSCH.N to configure the con-
UNITC.TYP, set C.TYP to 4
UNITSENSSPT.S, enable
UNITFN.MD, set FN.MD to
SCH.L submenu, enter the de-
To configure
Economizer Configurations — Under the Configu-
ration
configured:
ECON submenu, the following set points should be
EC.ENEconomizer Enabled?
EC.MNEconomizer Min.Position
EC.MXEconomizer Maximum Position
E.TRMEconomizer Trim for SumZ?
E.SELEcon Changeover Select
OA.E.COA Enthalpy Change Over Select
OA.ENOutdoor Enthalpy Compare Value
OAT.LHigh OAT Lockout Temp
O.DEWOA Dew Point Temp Limit
ORH.SOutside Air RH Sensor
CFM.COutdoor Air CFM Control
E.CFGEconomizer Operation Config
If the unit is equipped with an outdoor air flow station, the
following points in Configuration
be set.
If equipped with an outdoor flow station, make sure
Configuration
outdoor air cfm station is used, then the economizer will control to cfm, not a position, as long as the sensor is valid. Therefore, Configuration
sedes ConfigurationECONEC.MN. Without CFM or enthalpy control, the outdoor-air dampers will open to minimum
position when the supply fan is running. Outdoor-air dampers
will spring-return closed upon loss of power or shutdown of the
supply fan.
ECONEC.MN should always be set for
ECONCFM.C need to
ECONCFM.COCF.S is enabled. If an
ECONCFM.CO.C.MX super-
Indoor Air Quality Configurations
DEMAND CONTROL VENTILATION — Under Configuration
ters should be set to establish the minimum and maximum
points for outdoor air damper position during demand controlled ventilation (DCV):
absolute minimum vent position (or maximum reset) under
DCV.
minimum damper position (or with no DCV reset). This is also
referenced in the economizer section.
with the outdoor airflow station and will supersede
Configuration
door air cfm sensor is valid.
with the outdoor airflow station and will supersede
Configuration
door air cfm sensor is valid.
IAQDCV.C, the following configuration parame-
EC.MNEconomizer Min.Position
IAQ.MIAQ Demand Vent Min.Pos.
O.C.MXEconomizer Min. Flow
O.C.MNIAQ Demand Vent Min. Flow
Configuration
Configuration
Configuration
Configuration
IAQDCV.CIAQ.M is used to set the
IAQDCV.CEC.MN is used to set the
IAQDCV.CO.C.MX is used only
IAQDCV.CEC.MN as long as the out-
IAQDCV.CO.C.MN is used only
IAQDCV.CIAQ.M as long as the out-
Exhaust Configurations — The following exhaust
options should be configured.
Configuration
BP the following configurations may be adjusted:
BP.SPBuilding Pressure Set Point
BP.SOBP Set Point Offset
Under Configuration
rations may be adjusted:
BP.FSVFD/Act. Fire Speed
BP.MN VFD/Act. Min. Speed
BP.MX VFD Maximum Speed
Configuration
trol) — Under ConfigurationBP the following configurations may be adjusted:
BP.SP Building Pressure Setpoint (see note below)
Under Configuration
rations may be adjusted:
BP.FSVFD/Act. Fire Speed
BP.MN VFD/Act. Min. Speed
BP.MX VFD Maximum Speed
BP
BP
BF.CF=1 — Under Configuration
BP
BP.CF=2 (Return Fan Tracking Con-
BP
B.V.A the following configu-
B.V.A the following configu-
Under Configuration
urations may be adjusted:
FT.CFFan Track Learn Enable (see note below)
FT.TMFan Track Learn Rate (see note below, not
used when Fan Track Learning is disabled)
FT.STFan Track Initial DCFM
FT.MX Fan Track Max Clamp (see note below, not
used when Fan Track Learning is disabled)
FT.ADFan Track Max Correction (see note below,
not used when Fan Track Learning is disabled)
FT.OFFan Track Internl EEPROM (see note below,
FT.RM Fan Track Internal Ram (see note below, not
FT.RSFan Track Reset Internal (see note below, not
NOTE: These configurations are used only if Fan Track Learning is enabled. When Fan Track Learning is enabled, the control will add an offset to the Fan Track Initial DCFM
(Configuration
sure deviates from the Building Pressure Set Point (BP.SP).
Periodically, at the rate set by the Fan Track Learn Rate
(FT.TM) the delta cfm is adjusted upward or downward with a
maximum adjustment at a given instance to be no greater than
Fan Track Max correction (FT.AD). The delta cfm can not
ever be adjusted greater than or less than the Fan Track Max
Clamp (FT.MX).
not used when Fan Track Learning is disabled)
used when Fan Track Learning is disabled)
used when Fan Track Learning is disabled)
BP
BP
FA N. TFT.ST) if the building pres-
FA N. T the following config-
Set Clock on VFD — The clock set mode is used for
setting the date and time for the internal clock of the VFD. In
order to use the timer functions of the VFD control, the internal
clock must be set. The date is used to determine weekdays and
is visible in the fault logs. Refer to the VFD section in Appendix D on page 211 for information on operating the VFD and
using the keypad.
To set the clock, perform the following procedure from the
VFD keypad:
1. Select MENU (SOFT KEY 2). The Main menu will be
displayed.
2. Use the UP or DOWN keys to highlight TIME AND
DATE SET on the display screen and press ENTER
(SOFT KEY 2). The clock set parameter list will be
displayed.
3. Use the UP or DOWN keys to highlight CLOCK VISIBILITY and press SEL (SOFT KEY 2). This parameter
is used to display or hide the clock on the screen. Use the
UP or DOWN keys to change the parameter setting. Press
OK (SOFT KEY 2) to save the configuration and return
to the Clock Set menu.
4. Use the UP or DOWN keys to highlight SET TIME and
press SEL (SOFT KEY 2). Use the UP or DOWN keys to
change the hours and minutes. Press OK (SOFT KEY 2)
to save the configuration and return to the Clock Set
menu.
5. Use the UP or DOWN keys to highlight TIME FORMAT
and press SEL (SOFT KEY 2). Use the UP or DOWN
keys to change the parameter setting. Press OK (SOFT
KEY 2) to save the configuration and return to the Clock
Set menu.
6. Use the UP or DOWN keys to highlight SET DATE and
press SEL (SOFT KEY 2). Use the UP or DOWN keys to
change the day, month, and year. Press OK (SOFT KEY
2) to save the configuration and return to the Clock Set
menu.
7. Use the UP or DOWN keys to highlight DATE FORMAT and press SEL (SOFT KEY 2). Use the UP or
DOWN keys to change the parameter setting. Press OK
28
(SOFT KEY 2) to save the configuration and return to the
Clock Set menu.
8. Press EXIT (SOFT KEY 1) twice to return to the main
menu.
Programming Operating Schedules — The
ComfortLink controls will accommodate up to eight different
schedules (Periods 1 through 8), and each schedule is assigned
to the desired days of the week. Each schedule includes an occupied on and off time. As an example, to set an occupied
schedule for 8 AM to 5 PM for Monday through Friday, the
user would set days Monday through Friday to ON for Period
1. Then the user would configure the Period 1 Occupied From
point to 08:00 and the Period 1 Occupied To point to 17:00. To
create a different weekend schedule, the user would use Period
2 and set days Saturday and Sunday to ON with the desired Occupied On and Off times.
NOTE: By default, the time schedule periods are programmed
for 24 hours of occupied operation.
To create a schedule, perform the following procedure:
1. Scroll to the Configuration mode, and select CCN CONFIGURATION (CCN). Scroll down to the Schedule
Number (Configuration
password protection has been enabled, the user will be
prompted to enter the password before any new data is
accepted. The default password is 1111. SCH.N has a
range of 0 to 99. The default value is 1. A value of 0 is always occupied, and the unit will control to its occupied
set points. A value of 1 means the unit will follow a local
schedule, and a value of 65 to 99 means it will follow a
CCN schedule. Schedules 2-64 are not used as the control
only supports one internal/local schedule. If one of the 264 schedules is configured, then the control will force the
number back to 1. Make sure the value is set to 1 to use a
local schedule.
2. Enter the Time Clock mode. Scroll down to the LOCAL
TIME SCHEDULE (SCH.L) sub-mode, and press ENTER. Period 1 (PER.1) will be displayed.
3. Scroll down to the MON point. This point indicates if
schedule 1 applies to Monday. Use the ENTER command
to go into Edit mode, and use the UP or DOWN key to
change the display to YES or NO. Scroll down through
the rest of the days and apply schedule 1 where desired.
The schedule can also be applied to a holiday.
4. Configure the beginning of the occupied time period for
Period 1 (OCC). Press ENTER to go into Edit mode, and
the first two digits of the 00.00 will start flashing. Use the
UP or DOWN key to display the correct value for hours,
in 24-hour (military) time. Press ENTER and hour value
is saved and the minutes digits will start flashing. Use the
same procedure to display and save the desired minutes
value.
5. Configure the unoccupied time for period 1 (UNC). Press
ENTER to go into Edit mode, and the first two digits of
the 00.00 will start flashing. Use the UP or DOWN key to
display the correct value for hours, in 24-hour (military)
time. Press ENTER and hour value is saved and the minutes digits will start flashing. Use the same procedure to
display and save the desired minutes value.
6. The first schedule is now complete. If a second schedule
is needed, such as for weekends or holidays, scroll down
and repeat the entire procedure for period 2 (PER.2). If
additional schedules are needed, repeat the process for as
many as are needed. Eight schedules are provided.
IAQSC.OV=SCH.N). If
SERVICE TEST
General —
ture, which is intended to allow a service person to force the
unit into different modes of operation. To use this feature, enter
the Service Test category on the Navigator display and place
the unit into the test mode by changing Service Te st
from OFF to ON. The display will prompt for the password before allowing any change. The default password is 1111. Once
the unit enters the Service Test mode, the unit will shut down
all current modes.
TEST — The TEST command turns the unit off (hard stop)
and allows the unit to be put in a manual control mode.
STOP — The STOP command completely disables the unit
(all outputs turn off immediately). Once in this mode, nothing
can override the unit to turn it on. The controller will ignore all
inputs and commands.
S.STP — Setting Soft Stop to YES turns the unit off in an
orderly way, honoring any timeguards currently in effect.
FA N. F — By turning the FAN FORCE on, the supply fan is
turned on and will operate as it normally would, controlling
duct static pressure on VAV. SAV modulates from high to low
based on the software's algorithms. To remove the force, press
ENTER and then press the UP and DOWN arrows simultaneously.
The remaining categories: INDP, FA N S, AC.T.C, HMZR,EXVS, COOL, and HEAT are sub-menus with separate items
and functions. See Table 23.
The units are equipped with a Service Test fea-
TEST
Service Test Mode Logic — Operation in the Service
Test mode is sub-menu specific except for the INDP submenu. Leaving the sub-menu while a test is being performed
and attempting to start a different test in the new sub-menu will
cause the previous test to terminate. When this happens, the
new request will be delayed for 5 seconds. For example, if
compressors were turned on under the COOL sub-menu, any
attempt to turn on heating stages within the HEAT sub-menu
would immediately turn off the compressors and 5 seconds later the controller would honor the requested heat stages.
However, it is important to note that the user can leave a
Service Test mode to view any of the local display menus (Run
Status, Te m p era t u res, Pressures, Setpoints, Inputs, Outputs,
Configuration, Time Clock, Operating Modes, and Alarms)
and the control will remain in the Service Test mode.
Independent Outputs — The INDP sub-menu items
can be turned on and off regardless of the other category states.
For example, the humidifier relay or remote alarm/auxiliary relay can be forced on in the INDP sub-menu and will remain on
if compressor stages were requested in the COOL sub-menu.
Fans — Upon entering the FA NS sub-menu, the user will be
able to enact either a manual or automatic style of test operation. The first item in the sub-menu, Fan Test Mode Automatic
(Service Test
figured static pressure or building pressure control to begin as
in the application run mode. During this automatic mode, it is
possible to manually control condenser fans 1 to 4.
If Fan Test Mode Automatic (Service TestF. M O D ), is set to NO, then the user will have individual control over duct static pressure (VFD speed), building pressure
and condenser fan control. Additionally, the controller will protect the system from developing too much static pressure. If the
static pressure during manual control rises above 3 in. wg or if
the Static Pressure Set Point (Setpoints
2.5 in. wg and static pressure is 0.5 in. wg higher than SPSP,
then all options in the FANS menu will be cleared back to their
default OFF states.
FA NSF. M O D ), allows the fan and the con-
FA NS
SPSP) is greater than
29
Table 23 — Service Test
ITEMEXPANSIONRANGEUNITSCCN POINTWRITE STATUS
TESTService Test ModeON/OFFMAN_CTRL
STOPLocal Machine DisableYES/NOUNITSTOP
S.STPSoft Stop RequestYES/NOSOFTSTOP
FAN.FSupply Fan RequestYES/NOSFANFORC
F. MO DFan Test Automatic?YES/NOFANAUTO
E.POSEcon 1 Out Act. Cmd. Pos.0-100ECONFANS
SF.BYSupply Fan Bypass RelayON/OFFSFAN_TST
S.VFDSupply Fan Commanded %0-100%SFVFDTST
PE.BYPower Exhaust Bypass RelayON/OFFPEBY_TST
E.VFDExhaust Fan Commanded %0-100%EFVFDTST
A.VFDMtrMaster A Commanded %0-100%OAVFDTST
B.VFDMtrMaster B Commanded %0-100%OBVFDTST
CDF.1Condenser Fan Output 1ON/OFFCDF1_TST
CDF.2Condenser Fan Output 2ON/OFFCDF2_TST
CDF.3Condenser Fan Output 3ON/OFFCDF3_TST
CDF.4Condenser Fan Output 4ON/OFFCDF4_TSTCDF.5Condenser Fan Output 5ON/OFFCDF5_TST
AC.T.CCALIBRATE TEST-ACTUATORS
EC1.CEcon 1 Out Act.Cmd.Pos.0-100ECON1TST
E1.CLEconomizer Calibrate CmdYES/NOECONOCAL
E1C.AEcon 1 Out Act Ctl AngleCONCANG
EC2.CEcon 2 Ret Act.Cmd.Pos.0-100ECON2TST
E2.CLEconomzr 2 Calibrate CmdYES/NOECON2CAL
E2C.AEcon 2 Ret Act Ctl AngleECN2CANG
SP.AVAvg Suction Pressure A SP_A_AVG
DS.RSDig Scroll AutoTest Stat AC_DSST
EX.TSEXVS AUTO-COMPONENT TEST
EX.TRRun EXVs Auto-Test ON/OFFAC_EX
XT.STTest Status & Timer DD_TEXT
SH.SPEXV Superheat Ctrl SP SH_SP_CT
SH.A1Cir A EXV1 Superheat Tmp SH_A1
SH.A2Cir A EXV2 Superheat Tmp SH_A2
SH.B1Cir B EXV1 Superheat Tmp SH_B1
SH.B2Cir B EXV2 Superheat Tmp SH_B2
XA1SEXV A1 Auto-Test Status AC_XA1ST
XA2SEXV A2 Auto-Test Status AC_XA2ST
XB1SEXV B1 Auto-Test Status AC_XB1ST
XB2SEXV B2 Auto-Test Status AC_XB2ST
CD.TSCHARGE TST W/O LQD SENS.
CD.TRRun Chrg Tst w/o Lqd Sen ON/OFFAC_CDTR
CD.ET Test Status & TimerDD_TEXT
SCT.A Cir A Sat.Condensing Tmp SCTA
SST.A Cir A Sat.Suction Temp. SSTA
OAT Outside Air Temperature OAT
SCT.B Cir A Sat.Condensing Tmp SCTA
SST.B Cir A Sat.Suction Temp. SSTA
CL.TS CHARGE TST W LQD SENSORS
CL.TR Run Chrg Tst w/ Lqd Sen AC_CLTS
CD.ET Test Status & Timer DD_TEXT
SC.A Cir A Subcooling Temp. SC_A
CS.CA Calc. Cir A Subcool Temp CSC_A
CHG.A Cir A Over/Under Charge AC_CHG_A
OAT Outside Air Temperature OAT
SC.B Cir B Subcooling Temp. SC_B
CS.CB Calc. Cir B Subcool Temp CSC_B
CHG.B Cir B Over/Under Charge AC_CHG_B
ML.TS MLV/HGBP AUTO-TEST
ML.TR Run MLV/HGBP Auto-Test AC_MLV
ML.TDTest Status & Timer DD_TEXT
MLV Minimum Load Valve Relay ON/OFFMLV_TST
DP.A Cir A Discharge Pressure DP_A
ML.ST MLV/HGBP AutoTest Result AC_MLVST
SF.TS SUPPLY FAN AUTO-TEST
SF.TR Run Supply Fan Auto-Test ON/OFFAC_SF
SF.DT Test Status & Timer DD_TEXT
S.VFD VFD1 Actual Speed % VFD1_SPD
S.PWR VFD1 Actual Motor Power VFD1PWR
SP Static Pressure SP
SF.ST SF Auto-Test Result AC_SF_ST
31
Actuators — In the AC.T.C sub-menu, it will be possible
to control and calibrate actuators. Calibration is a mode in
which the actuator moves from 0% to the point at which the
actuator stalls, and it will then use this angular travel range as
its "control angle." It will also be possible to view the "control
angle" adopted by the actuator after a calibration.
Within this sub-menu, the user may calibrate and control the
three economizer actuators (2 outdoor air and 1 return air), hydronic/steam or humidifier actuators.
NOTE: Once a calibration has been started, the user cannot
exit test mode or select any other test mode operation until
complete.
Humidi-Mizer® System — In the Humidi-MiZer
(HMZR) sub-menu, it will be possible to control and calibrate
the Humidi-MiZer modulating valves (gas bypass and condenser) while the unit's compressors are OFF. Calibration is a
mode in which the unit software will first over-drive each
valve completely shut and to establish the "zero" open position. The controller then keeps track of the valve's position for
normal operation. During this calibration phase, a light ratcheting sound may be heard and will serve as proof of valve operation and closure. Note that the calibration feature in Service
Test is only provided as an additional troubleshooting tool.
This is to ensure that the valve will automatically go through
the calibration process anytime the unit is powered down, unit
power is cycled, or anytime there is a loss of communication
between the EXV board and the valve. There should be no
need to manually calibrate the valves under normal circumstances.
This sub-menu also allows manual manipulation of RHV
(reheat 3-way valve), the bypass valve, and condenser valve.
With the compressors and outdoor fans off, the user should
hear a light ratcheting sound during movement of the two
modulating valves. The sound can serve as proof of valve
operation.
Service Test
— On Humidi-MiZer equipped units, this item allows the user
to switch the reheat valve from ON to OFF or OFF to ON
when compressors are in the OFF position. When RHV is
switched to the ON position, the three-way valve will be energized. When RHV is switched to the OFF position, the threeway valve will be deenergized. To exercise this valve with a
Circuit B compressor commanded ON, go to (Service TestCOOLRHV). To view the actual valve position at any time,
the user can use the Outputs menu (Outputs
Service Test
Position) — On Humidi-MiZer equipped units, this item allows the user to exercise the valve that controls flow to the Circuit B condenser. The valve default position is 100% (completely open). The user will be able to adjust the valve from 0
to 100% through this function. As confirmation that the valve
is operational, the user should hear a light ratcheting sound as
the valve opens and closes. Note that this function is only operational when Circuit B compressors are OFF. To exercise this
valve with a Circuit B compressor commanded ON, go to
(Service Test
position at any time, the user can use the Outputs menu (Out-
puts
Service Test
Position) — On Humidi-MiZer equipped units, this item allows the user to exercise the valve that controls discharge gas
bypass around the Circuit B condenser. The valve default position is 0% (completely closed). The user will be able to adjust
the valve from 0 to 100% through this function. As confirmation that the valve is operational, the user should hear a light
ratcheting sound as the valve opens and closes. Note that this
function is only operational when Circuit B compressors are
OFF. To exercise this valve when a Circuit B compressor is
ON, go to (Service Test
HMZRRHV (Humidi-MiZer 3-Way Valve)
HMZRC.EXV (HMV-1: Condenser EXV
COOLC.EXV). To view the actual valve
COOLC.EXV).
HMZRB.EXV (HMV-2: Bypass EXV
COOLRHV).
COOLB.EXV). To view the
actual valve position at any time, the user can use the Outputs
menu (Outputs
Service Test
— On Humidi-Mizer configured units, this item allows the
user to calibrate the valve that controls flow to the Circuit B
condenser. Switching C.CAL to ON will instruct the unit software to over-drive the valve in the closing direction. This is to
ensure that the valve is completely shut and to establish the
"zero" open position. The controller then keeps track of the
valve's position for normal operation. During this calibration
phase, a light ratcheting sound may be heard and will serve as
proof of valve operation and closure. Note that the calibration
feature in Service Test is only provided as an additional troubleshooting tool. The valves will automatically go through the
calibration process anytime the unit is powered down, unit
power is cycled, or anytime there is a loss of communication
between the EXV board and the valve. There should be no
need to manually calibrate the valves under normal circumstances.
Service Test
On Humidi-Mizer configured units, this item allows the user to
calibrate the valve that controls discharge gas bypass around
the Circuit B condenser. Switching B.CAL to ON will instruct
the unit software to over-drive the valve in the closing direction. This is to assure that the valve is completely shut and to
establish the "zero" open position. The controller then keeps
track of the valve's position for normal operation. During this
calibration phase, a light ratcheting sound may be heard and
will serve as proof of valve operation and closure. Note that the
calibration feature in Service Test is only provided as an additional troubleshooting tool. The valves will automatically go
through the calibration process anytime the unit is powered
down, unit power is cycled, or anytime there is a loss of communication between the EXV board and the valve. There
should be no need to manually calibrate the valves under normal circumstances.
COOLB.EXV).
HMZRC.CAL (Condenser EXV Calibrate)
HMZRB.CAL (Bypass EXV Calibrate) —
Cooling — The cooling sub-menu offers many different
service tests.
• Service Test
Pos). It is possible to manually move the actuator during
the cooling test mode at all times, regardless if economizer cooling is suitable or not.
• Service Test
Point). Upon entering the cooling sub-menu, the static
pressure control item will default to the unit's static pressure set point. Thereafter, as mechanical cooling commences and the fan starts, the static pressure can be
manually adjusted during the cool mode without affecting the configured set point for normal runtime operation. By adjusting the static pressure set point, the user
can increase or decrease the supply airflow. Do not use a
static pressure that will exceed the system limits.
• Service Test
If this item is set to a non-zero value, the current
assigned compression stage for this unit will be selected
and enacted. Thereafter, the individual compressor will
be “read-only” and reflect the current staging state. In
addition, this item will automatically clamp the cooling
stages to its pre-configured maximum.
• Manual relay control of individual compressors. If the
cooling stage pattern request is set to zero, the user will
have the ability to manually control compressors. If the
user energizes mechanical cooling, the supply fan and
the outdoor fans will be started automatically. During
mechanical cooling, the unit will protect itself. Compressor diagnostics are active, monitoring for high discharge
pressure, low suction pressure, etc. The user can also
turn the minimum load valve on and off and set the digital scroll capacity (on units equipped with this device).
CoolE.POS (Econo Damper Command
COOLSP.SP (Static Pressure Set
COOLCL.ST (Requested Cool Stage).
32
• Service Test
Valve). On Humidi-MiZer equipped units, this item
allows the user to switch the reheat valve from ON to
OFF and vice versa. When RHV is switched to the ON
position, a three-way valve will be energized allowing
refrigerant flow to enter the reheat coil as if in a dehumidification mode or reheat mode. When RHV is
switched to the OFF position, the three-way valve will be
deenergized and the unit will revert back to normal cooling. Note that this function only allows manipulation of
RHV if a compressor on Circuit B has already been
turned ON. To manually exercise this valve without an
active Circuit B compressor, see the section titled Ser-
vice Test
tion at any time, the user can use the Outputs menu
(Outputs
• Service Test
EXV Position). On Humidi-MiZer equipped units, this
item allows the user to exercise the valve that controls
refrigerant flow to the Circuit B condenser. To exercise
the valve, RHV must first be switched to ON (Service
Te st
be commanded ON. The valve default position is 100%
(completely open). The user will be able to adjust the
valve from 0 to 100% through this function. The only
constraint on the valve position is that the percentage
sum of the bypass valve (Service TestB.EXV) and condenser valve must equal 100%. For
example, if the condenser modulating valve is only 80%
open, then the gas bypass modulating valve must remain
at least 20% open. The effect of closing the condenser
valve will be to increase the supply-air temperature
(additional reheat capacity). To view the actual valve
position at any time, the user can use the Outputs menu
(Outputs
• Service TestCOOLB.EXV (HMV-2: Bypass EXV
Position). On Humidi-MiZer equipped units, this item
allows the user to exercise the valve that controls discharge gas bypass around the Circuit B condenser. To
exercise the valve, RHV must first be switched to ON
(Service Test
sor must be commanded ON. The valve default position
is 0% (completely closed). The user will be able to adjust
the valve from 0 to 100% through this function. The only
constraint on the valve position is that the percentage
sum of the bypass valve and condenser valve (Service
Te st
if the condenser modulating valve is only 80% open,
then the gas bypass modulating valve must remain at
least 20% open. The effect of opening the bypass valve
will be to increase the supply air temperature (additional
reheat capacity). To view the actual valve position at any
time, the user can use the Outputs menu (OutputsCOOLB.EXV).
COOLRHV (Humidi-MiZer 3-Way
HMZRRHV. To view the actual valve posi-
COOLRHV).
COOLC.EXV (HMV-1: Condenser
COOLRHV) and a Circuit B compressor must
COOL
COOLC.EXV).
COOLRHV) and a Circuit B compres-
COOLC.EXV) must equal 100%. For example,
Heating — The Heat Test Mode sub-menu will offer auto-
matic fan start-up if not a gas-fired heat unit. On gas heat units,
the IGC (integrated gas controller) feedback from the gas control units will bring the fan on as required.
Within this sub-menu, control of the following is possible:
• Service Test
When this item is non-zero, the currently configured heat
type will energize the corresponding heat relay pattern
that reflects the requested stage. In addition the upper
limit will be clamped to reflect the maximum configured
number of stages. When non-zero, the heat relays will be
“read-only” and reflect the currently selected pattern.
• Service TestHEATHIR (Manual Heat Relay Control). If the “Heat
Stage Request” item is set to zero, it will be possible to
HEATHT.ST (Requested Heat Stage).
HEATHT.1-10, Service Test
individually control the heat relays, including the heat
interlock relay.
• Service Test
ity). If configured for modulating gas or SCR electric
heat, the user will be able to manually control the capacity of the modulating heat section (0 to 100%). The
requested heat stage must be greater than or equal to 1 or
heat relay 1 must be on before the control will accept a
modulating heat capacity request. If neither case is true,
the control will overwrite the modulating heat request
back to 0%.
• Service Test
tion). If configured for hydronic heat type, the user will
be able to manually control the positioning of the actuator which controls hot water (0 to 100%).
HEATH1.CP (Modulating Heat Capac-
HEATHTC.C (Ht Coil Command Posi-
SERVICE COMPONENT TESTS
Auto-component testing is the automated testing procedures
of a component or a group of components. Auto-component
testing can be used during commissioning of a unit to verify
that components are functioning properly. It can also be used as
a diagnostics routine for troubleshooting.
Control Description (Overview) — The 40/50N Se-
ries large rooftop unit is capable of performing auto-component tests. The auto-component tests appear in Navigator under
the Service Test menu (Service Test
CP.TSCompressor Auto-Test
DS.TSDig Scroll Auto-Test
EX.TSEXVS Auto-Component Test
CD.TSCharge Tst without Lqd Sens.
CL.TSCharge Tst with Lqd Sensors
ML.TSMLV/HGBP Auto-Test
SF.TSSupply Fan Auto-Test
RSLTComps Auto-Test Results
The unit must be in Service Test mode to perform the auto-
component tests (Service Test
Starting another test before a currently running test has
completed will cancel the running test and reset all outputs before starting the newly requested test.
Setting Service Test mode to "OFF" while running an auto-
component test will cancel the running test and reset all outputs.
For a complete description of notices, alerts and alarms ref-
erenced, see the Alarms and Alerts section.
Auto-component tests will have a status indicated by the
following:
1. Not Run
2. Running
3. Pass
4. Fail
The results of all auto-component tests will default to "NOT
RUN."
After power cycling the MBB, the results of all auto-com-
ponent tests will default to "NOT RUN."
If the required conditions for the test are not met, the test
will not be allowed to run. Note that there may be no indication
for the possible reasons why a test might not run.
For each auto-component test, if the verification criteria is
met, test status will display 'PASS,' if the verification criteria is
not met, test status will display 'FAIL.'
AC.DT):
TESTON).
33
For each auto-component test, the following information is
grouped in one screen: test status, component status, and values
of response parameters.
Auto-Component Test Control Descriptions —
following conditions:
1. Unit is not shut down due to failure (A152).
2. No compressors are on or requested on.
3. All compressors are available for staging.
The testing screen will display the following:
The compressor auto-component test functions by staging
all compressors ON and verifying a corresponding change in
the compressor CSB (compressor status board) and that circuit
suction pressure (SP.A/SP.B) decreases at least AC_SP_DR.AC_SP_DR (Auto-Component Suction Pressure Drop) is the
expected suction pressure drop when starting a compressor. It
is used during the compressor auto component test. When a
compressor is staged, the control verifies the suction pressure
drops by AC_SP_DR. The default value is 3, with a range of 0
to 10 psig.
Setting CP.TS=ON will perform the following automati-
cally:
1. Turn supply fan and required condenser fans ON.
2. After 25 seconds, stage up one compressor.
3. Verify CSB changes state properly.
4. Verify circuit SP decreases by AC_SP_DR within 30 sec-
5. Wait 30 seconds.
6. Repeat Steps 1-5 for next compressor until all compres-
7. Stage all compressors down and verify CSB changes
8. End test.
If a compressor is commanded ON and the corresponding
CSB indicates OFF, a "Compressor Failure" alert will be
logged:
If a compressor is commanded ON and the corresponding
CSB indicates ON while a decrease in suction pressure is not
detected, the "Suction Pressure Alert" will be logged:
The compressor auto-component test requires the
CP.TSONRun Compressor Auto-Test
CT.STStaging 1/8Test Status and Timer
SP.A188.5 psigCir A Suction Pressure
SP.B207.3 psigCir B Suction Pressure
RSLTComps Auto-Test Results
onds.
sors are staged ON.
state properly.
T051Circuit A, Compressor 1 Failure
T052Circuit A, Compressor 2 Failure
T053Circuit A, Compressor 3 Failure
T059Circuit A, Compressor 4 Failure
T054Circuit B, Compressor 1 Failure
T055Circuit B, Compressor 2 Failure
T056Circuit B, Compressor 3 Failure
T060Circuit B, Compressor 4 Failure
T062Circuit A, Suction Pressure Alert
T063Circuit B, Suction Pressure Alert
If a compressor is commanded OFF and the corresponding
CSB indicates ON, a "Compressor Stuck" alarm will be
logged:
A051Circuit A, Compressor 1 Stuck On Failure
A052Circuit A, Compressor 2 Stuck On Failure
A053Circuit A, Compressor 3 Stuck On Failure
A059Circuit A, Compressor 4 Stuck On Failure
A054Circuit B, Compressor 1 Stuck On Failure
A055Circuit B, Compressor 2 Stuck On Failure
A056Circuit B, Compressor 3 Stuck On Failure
A061Circuit B, Compressor 4 Stuck On Failure
Selecting "RSLT" from the compressor auto-test screen will
display the compressor auto-test result screen. The following
display is an example where the A2 compressor failed the test:
A1PassedComp A1 Auto-Test Result
A2FailedComp A2 Auto-Test Result
A3PassedComp A3 Auto-Test Result
A4PassedComp A4 Auto-Test Result
B1PassedComp B1 Auto-Test Result
B2PassedComp B2 Auto-Test Result
B3PassedComp B3 Auto-Test Result
B4PassedComp B4 Auto-Test Result
Digital Scroll Compressor (A1) Auto-Component Test — The digital scroll auto-component test re-
quires the following conditions:
1. Unit is not shut down due to failure (A152).
2. DG.A1=YES (digital scroll compressor installed on A1
and enabled).
3. OAT<DSMAXOAT (digital scroll maximum OAT).
4. No compressors are on or requested on.
5. Compressor A1 is available to start.
The testing screen will display the following:
DS.TRONRun Dig Scroll Auto-Test
DS.DTRunning 1/1Test Status and Timer
A1.CP50%Compressor A1 Capacity
SP.A188.5 psigCir A Suction Pressure
SP.AV185.5 psigAvg Suction Pressure A
DS.STRunningDig Scroll AutoTest Stat
The digital scroll auto-component test functions by running
the scroll compressor (A1.CP) at 50% and 100% while verifying a change in average circuit suction pressure (SP.AV) ofAC_DS_SP.
The digital scroll auto-component suction pressure drop
(AC_DS_SP) will default to 2.5 psig with a range of 0 to
10 psig.
Setting DS.TS=ON will perform the following:
1. Turn supply fan and condenser fans ON.
2. Wait for 25 seconds.
3. Set digital scroll capacity to 50%.
4. Verify circuit SP.AV decreases by AC_DS_SP within 30
seconds.
5. Wait 2 minutes.
6. Set digital scroll capacity to 100%.
7. Verify circuit SP.AV decreases AC_DS_SP within 30 sec-
onds.
8. End test.
34
If SP.AV is verified to change properly at 50% and 100%
capacity, then DS.ST= PASS, otherwise DS.ST=FAIL.
EXV Auto-Component Test — The EXV auto-com-
ponent test requires the following conditions:
1. Unit is not shut down due to failure (A152).
2. OAT>70 F.
3. No compressors are on or requested on.
4. A1, B1, and B2 are available on a 75-ton unit, A1, A2,
B1, B2 are available on 90, 105, 120, 130, and 150-ton
units.
The testing screen will display the following:
EX.TRONRun EXVs Auto-Test
XT.STRunning
CMPS
SH.SP12.0 dFEXV Superheat Ctrl SP
SH.A111.7 dFCir A EXV1 Superheat Temp
SH.A212.4 dFCir A EXV2 Superheat Temp
SH.B112.4 dFCir B EXV1 Superheat Temp
SH.B212.1 dFCir B EXV2 Superheat Temp
XA1SRunningEXV A1 Auto-Test Status
XA2SRunningEXV A2 Auto-Test Status
XB1SRunningEXV B1 Auto-Test Status
XB2SRunningEXV B2 Auto-Test Status
The EXV auto-component test functions by staging compressor A1, B1, and B2 for a 75-ton unit and A1, A2, B1, B2
for other units, and verifying the superheat is within ±
AC_SH_DB (auto-component test superheat deadband) of the
superheat setpoint (SH.SP).
The auto-component test superheat deadband
(AC_SH_DB) will default to 2 F with a range of 0° to 10 F.
Setting XA.TS=ON will perform the following:
1. Stage compressors A1/B1/B2 for 75-ton unit, A1/A2/B1/
B2 for other units.
2. Allow compressors to run for 5 minutes
3. Verify that SH.A1, SH.A2, SH.B1, and SH.B2 have stabilized to SH.SP ± AC_SH_DB. If all four superheats are
SH.SP ± AC_SH_DB then set PASS status and end test.
4. If any superheat is outside SH.SP ± AC_SH_DB, allow
compressors to run for 5 more minutes
5. Set PASS/FAIL status according to whether each superheat has stabilized to SH.SP ± AC_SH_DB and end test
If SH.SP ± AC_SH_DB then XA.ST= PASS, otherwise
XA.ST=FAIL.
If the EXV superheat is not within SH.SP ± SH.DB, the su-
perheat alert will be logged:
T064EXV A1 Superheat Outside Range
T065EXV A2 Superheat Outside Range
T066EXV B1 Superheat Outside Range
T067EXV B2 Superheat Outside Range
CD.TSONRun Chrg Test without Lqd Sen
CD.ETRunningTest Status and Timer
SCT.A105.3 FCir A Sat. Condensing Temp
SST.A50.4 FCir A Sat. Suction Temp
OAT66.3 FOutside Air Temp
SCT.B106.5 FCir A Sat. Condensing Temp
SST.B49.8 FCir A Sat. Suction Temp
When no liquid sensors are installed, all compressors and
outdoor fans of both circuit A and B are commanded to be ON.
The operator will read OAT, SCT.A, and SST.A, in order to
then compare the values to the A charging chart to determine if
refrigerant in circuit A is properly charged. The operator reads
OAT, SCT.B, and SST.B, in order to then compare the values to
the B charging chart to determine if refrigerant in Circuit B is
properly charged. Thus this is a semi-auto test because the operator intervention is required to determine the test results. No
test results are displayed.
Setting CT.ST=ON will perform the following:
1. Command supply fan ON.
2. Command all A and B Circuit outdoor fans ON.
3. Stage all A and B Circuit compressors ON.
4. Let compressors run 5 minutes.
5. Prompt user to read charging charts
6. Let compressors run 5 minutes.
7. End test.
Refrigerant Charge Auto Test (with Liquid
Sensors) — The refrigerant charge auto test with liquid
sensors requires the following conditions:
1. Unit is not shut down due to failure (A152).
2. Liquid sensors installed and enabled.
3. OAT>75 F.
4. No compressors are on or requested on.
5. All compressors are available for staging.
6. Calculated subcooling both circuit A and B is < -1.5.
7. SST.A and SST.B > AC_SST_M.
The test screen will display the following:
CL.TSONRun Chrg Tst with Lqd Sen
CD.ETRunningTest Status and Timer
SC.A–10.3 dFCir A Subcooling Temp
CS.CA–6.2 dFCalc Cir A Subcooling Temp
CHG.A0.5 lbCir A Over/Under Charge
OAT80.3 FOutside Air Temp
SC.B–10.6 dFCir B Subcooling Temp
CS.CB–6.6 dFCalc Cir B Subcool Temp
CHG.B–1.3 lbCir B Over/Under Charge
All compressors and outdoor fans of circuits A and B are
commanded to ON. OAT and subcooling (SC.A) will then be
used by the algorithm as described in the steps below to determine the refrigerant charge level.
AC_SST_M (Auto-Component Minimum SST) is the mini-
mum SST read during a charge determination test. If at any
time during the test, SST.A or SST.B is less than AC_SST_M,
then the test shall be cancelled. AC_SST_M shall default to 40
and have a range of 20 to 100.
Setting CT.ST=ON will perform the following:
1. Command supply fan ON.
2. Command all A and B circuit outdoor fans ON.
35
3. Stage all A and B circuit compressors ON.
Fig. 3 — Plot A: OAT vs Subcooling
a48-8785
4
3
2
1
0
-1
-6
-4
-2
02 4
6
Charge (lb)
Delta Subcooling (F)
Poly. (A)
B
A
Poly. (B)
y = 0.0137x2 + 0.4519x + 0.0036
R
2
= 0.9996
y = 0.0221x2 + 0.5284x - 0.0072
R
2
= 0.9995
8
-2
-3
Fig. 4 — Plot B: Delta Subcooling vs Charge
a48-
4. Wait 5 minutes.
5. Calculate CHG.A (0 lb indicates proper charge, 0.5 lb in-
dicates 0.5 lb of over charge, and -0.5 lb indicates 0.5 lb
of under charge) as follows:
a. Calculate subcooling (CS.CA) as function of OAT
according to curve fit in plot A, Fig. 3.
b. SC_Delta =CS.CA - SC.A.
c. CHG.A = function (SC_Delta) according to plot B,
Fig. 4.
6. Calculate CHG.B as follows:
a. Calculate subcooling (CS.CA) as function of OAT
according to curve fit in plot A.
b. SC_Delta = CS.CB - SC.B.
c. CHG.B = function (SC_Delta) according to plot B.
7. End test.
NOTE: Charge level will be used as a guideline only.
A charge of -99.9 indicates the charge has not been deter-
mined.
The charge auto-component test uses the following configu-
This test assumes the charge determination test has been run
successfully. If the charge is low or high, the results of this test
will not be valid.
The filter drier auto-component test functions by staging all
compressors and verifying the discharge pressure minus liquid
pressure does not exceed the calculated condenser pressure
drop by ± AC_FD_DP psig. AC_FD_DP (Auto-component
Filter Drier Differential Pressure) is the filter drier auto-component test by staging all compressors and verifying the discharge
pressure minus liquid pressure does not exceed the calculated
condenser pressure drop by + AC_FD_DP psig. The calculated condenser pressure drop shall be calculated as a function of
OAT according to curve fit in plot C, Fig. 5. AC_FD_DP shall
have a default value of 20 psig with a range of 10 to 50 psig.
Setting FD.TS=ON will perform the following:
1. Command supply fan ON.
2. Command all outdoor fans ON.
3. Stage all compressors ON.
4. Let compressors run 5 minutes.
5. Verify DP.A - LP.A is within calculated condenser pres-
sure drop ± AC_FD_DP; set FDA.S = PASS, otherwise
set FDA.S = FAIL
6. Verify DP.B - LP.B is within calculated condenser pres-
sure drop ± AC_FD_DP; set FDB.S=PASS, otherwise
set FDB.S=FAIL
7. End Test.
If FDA/B.S is 'FAIL,' the filter drier alert will be logged:
A130Circuit A Filter Drier Alert
A131Circuit B Filter Drier Alert
36
Minimum Load Valve (MLV) Auto-Component
45
40
35
30
25
20
50
70
90
110
130
Delta Pressure (psi)
Outdoor Air Temperature (F)
∆P cond A
Poly. (∆P cond A)
∆P cond B
Poly. (∆P cond B)
y = 0.0003x3 + 0.0985x2 - 10.336x + 389.27
R
2
= 0.997
y = 0.0003x3 + 0.098x2 - 10.176x + 378.29
R
2
= 0.9958
Fig. 5 — Plot C: OAT vs Delta Condenser Pressure
a48-8787
Test —
pass valve (HGBV).
ing conditions:
1. Unit is not shut down due to failure (A152).
2. MLV=ENBL.
3. No compressors are on or requested on.
4. Compressor A1 is available to start.
discharge pressure when MLV is closed to that when MLV is
open, and verifying DP.A decreases by at least AC_MLVDR.
default to 5 psig with a range of 0 to 10 psig.
1. Command A1 ON and MLV OFF.
2. Let circuit stabilize for 5 minutes and save DP.A
3. Command MLV ON.
4. Let circuit stabilize for 5 minutes and record DP.A
Minimum load valve is also referred to as hot gas by-
The hot gas bypass auto-component test requires the follow-
The test screen will display the following:
ML.TSNoRun MLV/HGBO Auto-Test
ML.DTRunning 1/1 Test Status and Timer
MLVOffMinimum Load Valve Relay
DP.A331.3 psigCir A Discharge Pressure
ML.STRunningMLV/HGBP AutoTest Result
The MLV auto-component test functions by comparing the
The auto-component MLV deadband (AC_MLVDR) will
Setting T. ML V=ON will perform the following:
(recorded).
(current)
If DP.A (recorded) - DP.A (current) > AC_MLVDR then
Supply Fan Auto-Component Test — The supply
fan auto-component test requires the following conditions:
1. Unit is not shut down due to failure (A152).
2. Supply fan VFD not in bypass mode.
3. Power exhaust or return fan (if enabled) not in bypass
mode.
4. Supply fan not on.
The test screen will display this:
SF.TSNoRun Supply Fan Auto-Test
SF.DTRunningTest Status and Timer
S.VFD0%VFD1 Actual Speed %
S.PWR0.00 kWVFD1 Actual Motor Power
SP0.00˝ H20Static Pressure
SF.STPassSF Auto-Test Result
The supply fan auto-component test functions by commanding the supply fan to minimum speed (STATPMIN), and
verifying that VFD power (S.PWR) and duct static pressure
(SP) is increasing.
Setting SF.TS=ON will perform the following:
1. Record S.PWR and SP.
2. Command S.VFD to STATPMIN and let run 5 minutes.
3. Verify S.PWR increases.
4. If SP.CF=ENBL and SP.S=ENBL, verify SP increases.
5. End test.
After letting the supply fan run and stabilize for 5 minutes,
the control will verify S.PWR has increased and SP (if enabled) has increased.
If both S.PWR and SP (if enabled) have increased,
SF.ST=PASS, otherwise SF.ST=FAIL.
Power Exhaust Fan Auto-Component Test —
The power exhaust fan auto-component test requires the following conditions:
1. Unit is not shut down due to failure (A152).
2. Supply fan VFD not in bypass mode.
3. Power exhaust fan VFD not in bypass mode.
4. BP.CF=VFD PWR EXH (Building pressure is controlled
by exhaust fan).
5. Supply fan not on.
6. Power exhaust not on.
Test screen will display the following:
The power exhaust fan auto-component test functions by
commanding the supply fan to minimum speed (STATPMIN)
and verifying that exhaust VFD speed (E.VFD) and power
(E.PWR) increase while building pressure (BP) is modulated
to within ± AC_PE_DB of BPSP. AC_PE_DB will have a de-
fault value of 0.02 in. wg and a range of 0 to 0.25 in. wg.
Setting (PE.TS) =ON will perform the following:
1. Record E.PWR and E.VFD.
2. Command S.VFD to STATPMIN.
3. Open economizer to ECONOMIN.
4. Allow building pressure task to modulate E.VFD and let
run 5 minutes.
5. Verify E.VFD increases.
6. Verify E.PWR increases.
7. Verify BP within BPSP ± AC_PE_DB.
8. End test.
37
After letting the power exhaust run and stabilize for 5 min-
Fig. 6 — Plot D: SCT MAX vs OAT
a48-8788
utes, the control will verify E.PWR has increased and BP is
within BPSP ± AC_PE_DB.
If E.PWR has increased and BP is within BPSP ±
AC_PE_DB, PF.ST=PASS, otherwise SF.ST=FAIL.
Return Fan Auto-Component Test — The return
fan auto-component test requires the following conditions:
1. Unit is not shut down due to failure (A152).
2. Supply fan VFD not in bypass mode.
3. Return fan VFD not in bypass mode.
4. BP.CF=FAN TRACKING (Building pressure controlled
by keeping a constant difference between supply airflow
and return airflow).
The return fan auto-component test will function by commanding the supply fan to minimum speed (STATPMIN), and
verifying that return VFD power (R.PWR) is increasing and
building pressure (BP) is decreasing.
Setting RF.TS=ON will perform the following:
1. Record R.PWR, D.CFM, and BP.
2. Command S.VFD to STATPMIN.
3. Open economizer to ECONOMIN.
4. Allow building pressure task to modulate R.VFD and let
run 5 minutes.
5. Verify R.PWR increases.
6. Verify D.CFM increases
7. Verify BP increases.
8. End test.
After letting the return fan run and stabilize for 5 minutes,
the control will verify R.PWR has increased and BP has
changed.
If R.PWR has increased and BP has changed,
RF.ST=PASS, otherwise RF.ST=FAIL.
Condenser Fans (Outdoor Fans) Auto-Component Test —
quires the following conditions:
1. Unit is not shut down due to failure (A152).
2. OAT>70 F.
3. No compressors are on or requested on.
4. All compressors are available for staging.
Test screen will display the following:
CF.TSON
SCT.A105.3 F
SCA.H115.0 F
SCT.B108.3 F
SCB.H117.0 F
OAT76.3 F
CF.STRunning
The condenser fans auto-component test re-
The condenser fans auto-component test functions by commanding to ON all compressors and outdoor fans and verify
that Saturated Condensate Temperature (SCT) is less than the
calculated SCA.H and SCB.H for the corresponding circuit.
SCA.H and SCB.H depend on OAT and are different for each
unit size and circuit, see Plot D, Fig. 6.
Setting CF.TS=ON will perform the following:
1. Command supply fan ON.
2. Command all condenser fans ON.
3. Stage all compressors ON.
4. Let compressors run for 5 minutes.
5. Verify SCT.A < SCA.H and SCT.B <SCB.H.
6. End test.
After letting the condenser fans run and stabilize for 5 min-
utes, the control will verify SCT.A<SCA.H and SCT.B <SCB.H.
If SCT.A<SCA.H and SCT.B<SCB.H, CF.ST=PASS, oth-
erwise CF.ST=FAIL.
150
140
y = 0.0057x
130
120
110
SCT MAX (F)
100
90
80
60
2
+ 2.0025x2 - 13.752
2
R
= 0.9918
80
Outdoor Air Temperature (F)
100
SCTA
SCTB
Avg
Poly. (Avg)
120
Economizer Auto-Component Test — The econo-
mizer auto-component test requires the following conditions:
1. Unit is not shut down due to failure (A152).
2. EC.EN=YES (Economizer is enabled).
3. ABS (OAT-RAT)>10 F. (There is at least 10F difference
between OAT and RAT).
4. Supply fan VFD not in bypass mode.
5. Power exhaust or return fan (if enabled) not in bypass
mode.
6. Supply fan not on.
Test screen will display the following:
EC.TSON
S.VFD20.0 %
E.POS100.0 %
O.CFM 4000 cfm
OAT65 F
RAT75 F
SAT65 F
MAT65 F
EC.STRunning
The economizer auto-component test will verify economiz-
er operation at the 0% and 100% position. It will perform this
test by commanding the supply fan to minimum speed
(STATPMIN), modulating the economizer position, and veri-
fying SAT changes to within the auto-component test economizer deadband (AC_EC_DB) of OAT and RAT. AC_EC_DB
will default to 4 F with a range of 0 to 10 F.
38
Setting EC.TS=ON will perform the following:
1. Command S.VFD to STATPMIN.
2. Open E.POS to 100% and let run 5 minutes.
3. Verify SAT=OAT ± AC_EC_DB.
4. Close E.POS to 0% and let run 5 minutes.
5. Verify SAT=RAT ± AC_EC_DB.
6. End test.
If SAT=OAT ± AC_EC_DB when E.POS=100% and
SAT=RAT ± AC_EC_DB when E.POS=0%, EC.ST=PASS,
otherwise EC.ST=FAIL.
Humidi-MiZer Auto-Component Test — The Hu-
midi-MiZer auto-component test requires the following conditions:
1. Unit is not shut down due to failure (A152).
2. D.SEL=DH - HUMDZR (Humidi-MiZer system is con-
figured to perform dehumidification).
3. No compressors are on or requested on.
4. Compressor A1 is available to start.
Test screen will display the following:
HZ.TSON
RHVOFF
C.EXV100%
B.EXV0%
EDT55 F
SAT55 F
HZ.STRunning
The Humidi-MiZer auto-component test will verify Hu-
midi-MiZer operation in cooling, subcooling and reheat
modes. It will perform this test by commanding compressor B1
ON, adjusting RHV (3-way reheat valve), C.EXV (condenser
modulating valve) and B.EXV ( bypass modulating valve), and
comparing SAT to EDT (evaporator discharge temperature).
Setting HZ.TS=ON will perform the following:
1. Command compressor B1, supply fan, and condenser
fans ON.
2. Run cooling mode by setting RHV=OFF, C.EXV=100%,
B.EXV=0%.
3. Allow to run for 5 minutes and verify SAT=>EDT. Re-
cord SAT and EDT.
4. Run subcooling mode by setting RHV=ON,
C.EXV=100%, B.EXV=0%.
5. Allow to run for 5 minutes and verify EDT is less than the
value recorded in Step 3 and SAT - EDT > 2 F.
6. Run reheat mode by setting RHV=ON, C.EXV=0%,
B.EXV=100%.
7. Allow to run for 5 minutes and verify SAT-EDT>5 F.
8. End test.
If all SAT/EDT comparisons are verified, HZ.ST=PASS,
otherwise HZ.ST=FAIL.
THIRD PARTY CONTROL
Thermostat —
the thermostat inputs:
Y1 = first stage cooling
Y1 and Y2 = first and second stage cooling
W1 = first stage heating
W1 and W2 = first and second stage heating
G = supply fan
The method of control would be through
Alarm Output — The alarm output is 24-v at TB201-X
and TB201-C. The contact will provide relay closure whenever
the unit is under an alert or alarm condition (5 va maximum).
Remote Switch — The remote switch may be configured
for three different functions. Under Configuration
RM.CF to one of the following:
Under Configuration
occupancy switch can be set to either a normally open or normally closed switch input. Normal is defined as either unoccupied, start or “not currently overridden,” respective to the
RM.CF configuration.
With RM.CF set to 1, no time schedules are followed and
the unit follows the remote switch only in determining the state
of occupancy.
With RM.CF set to 2, the remote switch can be used to shut
down and disable the unit, while still honoring timeguards on
compressors. Time schedules, internal or external, may be run
simultaneously with this configuration.
With RM.CF set to 3, the remote input may override an unoccupied state and force the control to go occupied mode. As
with the start/stop configuration, an internal or external time
schedule may continue to control occupancy when the switch
is not in effect.
IAQSW.LG, RMI.L, the remote
UNIT, set
VFD Control — Supply duct static pressure control of the
VFD driving the supply fan may be left under unit control or be
externally controlled. To control the VFD externally with a 4 to
20 mA signal, set SP.RS to 4 (VFD CONTROL), under the
Configuration
trol. When SP.RS = VFD CONTROL, the static pressure reset
function acts to provide direct VFD speed control where 4 mA
= 0% speed and 20 mA = 100% (SP.MN and SP.MX will over-
ride). Note that SP.CF must be set to 1 (ENABLE) prior to
configuring SP.RS = VFD CONTROL. Failure to do so could
result in damage to ductwork due to overpressurization.
In effect, this represents a speed control signal "pass
through" under normal operating circumstances. The Com-fortLink controller overrides the third party signal for critical
operation situations, most notably smoke and fire control.
Wire the input to the controls expansion module (CEM) using TB202-6 and TB202-7. An optional CEM board is
required.
See Appendix D and the VFD literature supplied with the
unit for further information on the VFD.
SP menu. This will set the reset to VFD con-
Supply Air Reset — With the installation of the control
expansion module (CEM), the ComfortLink controls are capable of accepting a 4 to 20 mA signal, to reset the supply-air
temperature up to a maximum of 20 F.
Under Configuration
RSET - external 4 to 20 mA supply air reset control). The 4 to
20 mA input to the control system (TB202-9 and TB202-8),
will be linearized and range from 0° to 20 F. For example, 4
mA = 0° F reset, 12 mA = 10° F reset and 20 mA = 20° F reset.
EDT.R set RS.CF to 3 (4-20 SA
Demand Limit Control — The term demand limit con-
trol refers to the restriction of the machine's mechanical cooling
capacity to control the amount of power that a machine may
use.
Demand limiting is possible via two means:
Two discrete inputs tied to demand limit set point percentages.
OR
A 4 to 20 mA input that can reduce or limit capacity linearly to
a set point percentage.
39
In either case, it will be necessary to install a controls expansion module (CEM). The control interfaces to a switch input at
TB202-10 and TB202-11.
DEMAND LIMIT DISCRETE INPUTS — First, set DM.L.S
in Configuration
When Inputs
OFF, the control will not set any limit to the capacity, and
when ON, the control sets a capacity limit to the Configura-
tion
BP
Likewise, when Inputs
no. 2) is OFF, the control will not set any limit to the capacity,
and when ON, the control sets a capacity limit to the Configu-
ration
BP
If both switches are ON, Inputs
as the limiter of capacity.
Under Configuration
appropriately for the action desired. Set the DL1.L and DL2.L
configurations. They can be set normally open or normally
closed. For example, if DL1.L is set to OPEN, the user will
need to close the switch to cause the control to limit capacity to
the demand limit 1 set point. Likewise, if DL1.L is set to CLSE
(closed), the user will need to open the switch to cause the control to limit capacity to the demand limit 1 set point.
DEMAND LIMIT 4 TO 20 mA INPUT — Under Configu-
ration
BP
20 mA control). Under the same menu, set D.L.20 to a value
from 0 to 100 to set the demand limit range. For example, with
D.L.20 set to 50, a 4 mA signal will result in no limit to the
capacity and 20 mA signal will result in a 50% reduction in
capacity.
BP
DMD.LD.L.S1 set point.
DMD.LD.L.S2 set point.
DMD.L, set configuration DM.L.S to 2 (2 = 4 to
DMD.L to 1 (2 switches).
GEN.IDL.S1 (Demand Switch no. 1) is
GEN.IDL.S2 (Demand Switch
GEN.IDL.S2 is used
IAQSW.LG, set the logic state
Economizer/Outdoor Air Damper Control —
There are multiple methods for externally controlling the economizer damper.
IAQ DISCRETE INPUT CONFIGURATION — The IAQ
(indoor air quality) discrete input configuration requires a
CEM module (optional) to be installed and an interface to a
switch input at TB202-12 and TB202-13. The state of the input
on the display can be found at Inputs
Before configuring the switch functionality, first determine
how the switch will be read. A closed switch can indicate either
a low IAQ condition or a high IAQ condition. This is set at
Configuration
what a low reading would mean based on the type of switch being used. Setting IAQ.L to OPEN means that when the switch
is open the input will read LOW. When the switch is closed, the
input will read HIGH. Setting IAQ.L to CLSE (closed) means
that when the switch is closed the input will read LOW, and
therefore, when the switch is open the switch will read HIGH.
There are two possible configurations for the IAQ discrete
input. Select item Configuration
and configure for either 1 (IAQ Discrete) or 2 (IAQ Discrete
Override).
IQ.I.C
Discrete), and the switch logic (Configuration
SW.LGIAQ.L) is set to OPEN, then an open switch reads
low and a closed switch reads high.
If the switch is open, the economizer will be commanded to
the IAQ Demand Vent Minimum Position. If the outdoor flow
station is installed and outdoor air cfm can be read, the economizer will move to the IAQ Demand Vent Minimum Flow
CFM control setting.
These settings may be adjusted and are located here:
Configuration
Configuration
If the switch is closed, the IAQ reading will be high and the
economizer will be commanded to the Economizer Minimum
Position. If the outdoor airflow station is installed and outdoor
IAQSW.LGIAQ.L. The user can set
= 1 (IAQ Discrete) — If the user sets IQ.I.C to 1 (IAQ
IAQDCV.CIAQ.M
IAQDCV.CO.C.MN
AIR.QIAQ.I.
IAQAQ.CFIQ.I.C
IAQ
air cfm can be read, the economizer will move to the Economizer Minimum Flow CFM control setting.
These settings may be adjusted and are located here:
Configuration
Configuration
IQ.I.C
= 2 (IAQ Discrete Override) — If the user sets IQ.I.C
to 2 (IAQ Discrete Override), and ConfigurationSW.LGIAQ.L is set to OPEN, then an open switch reads low
and a closed switch reads high.
If the switch reads low, no action will be taken. If the switch
reads high, the economizer will immediately be commanded to
the IAQ Economizer Override Position. This can be set from 0
to 100% and can be found at ConfigurationIQ.O.P.
FAN CONTROL FOR THE IAQ DISCRETE INPUT —
Under Configuration
crete Input Fan Configuration) must also be set. There are
three configurations for IQ.I.F. Select the configuration which
will be used for fan operation. This configuration allows the
user to decide whether the IAQ discrete switch will start the
fan (if the supply fan is not already running), and in which state
of occupancy the fan will start.
IQ.I.F = 0Minimum Position Override Switch input
IQ.I.F = 1Minimum Position Override Switch input
IQ.I.F = 2Minimum Position Override Switch input
IAQ ANALOG INPUT CONFIGURATION — This input is
an analog input located on the main base board (MBB). There
are 4 different functions for this input. The location of this configuration is at Configuration
The functions possible for IQ.A.C are:
• 0 = no IAQ analog input
• 1 = IAQ analog input
• 2 = IAQ analog input used to override to a set position
• 3 = 4 to 20 mA 0 to 100% economizer minimum position
control
• 4 = 0 to 10,000 ohms 0 to 100% economizer minimum
position control
Options 2, 3, and 4 are dedicated for third party control.
IQ.A.C
= 2 (IAQ Analog Input Used to Override) — Under
Configuration
Override Position). The IQ.O.P configuration is adjustable
from 0 to 100%. These configurations are also used in conjunction with Configuration
20 mA Fan Configuration). There are three configurations for
IQ.A.F and they follow the same logic as for the discrete input.
This configuration allows the user to decide (if the supply fan is
not already running), if the IAQ Analog Minimum Position
Override input will start the fan, and in which state of occupancy the fan will start.
IQ.A.F = 0IAQ analog sensor input cannot start the
IQ.A.F = 1IAQ analog sensor input can start the supply
IQ.A.F = 2IAQ analog sensor input can start the supply
If IQ.A.F is configured to request the supply fan, then
configurations D.F.ON and D.F.OF need to be set. These
configuration settings are located under ConfigurationIAQAQ.SP and configure the fan override operation based
on the differential air quality (DAQ). If DAQ rises above
D.F.ON, the control will request the fan on until DAQ falls be-
low D.F.OF.
IAQDCV.CEC.MN
IAQDCV.CO.C.MX
IAQAQ.SP
IAQAQ.CF, the IQ.I.F (IAQ Dis-
will not start fan
will start fan in occupied mode only
will start fan in both occupied and unoccupied modes
IAQAQ.CFIQ.A.C.
IAQAQ.SP, set IQ.O.P (IAQ Economizer
IAQAQ.CFIQ.A.F (IAQ 4 to
supply fan
fan in occupied mode only
fan in both occupied and unoccupied modes
IAQ
40
NOTE: If D.F.ON is configured below DAQ.H, the unit is in
occupied mode, and the fan was off, then DAQ rose above
D.F.ON and the fan came on, the economizer will go to the
economizer minimum position (EC.MN).
The 4 to 20 mA signal from the sensor wired to TB201-8
and TB201-7 is scaled to an equivalent indoor CO
the parameters IQ.R.L and IQ.R.H located under the Configu-
ration
IAQAQ.SR menu. The parameters are defined such
(IAQ) by
2
that 4 mA = IQ.R.L and 20 mA = IQ.R.H. When the differential air quality DAQ (IAQ – OAQ.U) exceeds the DAQ.H set
point (Configuration
IAQAQ.SP menu) and the supply
fan is on, the economizer minimum vent position (Configura-
tion
IAQDCV.CEC.MN) is overridden and the damper
is moved to the IQ.P.O configuration. When the DAQ falls be-
low the DAQ.L set point (Configuration
IAQAQ.SP
menu), the economizer damper is moved back to the minimum
vent position (EC.MN).
NOTE: Configuration OAQ.U is used in the calculation of the
trip point for override and can be found under Configura-
tion
IAQAQ.SP.
IQ.A.C
= 3 (4 to 20 mA Damper Control) — This configuration will provide full 4 to 20 mA remotely controlled analog input for economizer minimum damper position. The 4 to 20 mA
signal is connected to terminals TB201-8 and TB201-7. The
input is processed as 4 mA = 0% and 20 mA = 100%, thereby
giving complete range control of the effective minimum
position.
The economizer sequences can be disabled by unpluging
the enthalpy switch input and not enabling any other economizer changeover sequence at Configura-
tion
ECONE.SEL. Complete control of the economizer
damper position is then possible by using a 4 to 20 mA economizer minimum position control or a 0 to 10,000-ohm 0 to
100% economizer minimum position control via configuration
decisions at Configuration
IAQAQ.CFIQ.A.C.
To disable the standard enthalpy control input function,
unplug the enthalpy switch and provide a jumper from TB2016 to TB201-5 (see wiring diagrams in Major System Components section on page 127).
IQ.A.C
= 4 (10,000 ohm Potentiometer Damper Control)
— This configuration will provide input for a 10,000 ohm linear potentiometer that acts as a remotely controlled analog input for economizer minimum damper position. The input is
processed as 0 ohms = 0% and 10,000 ohms = 100%, thereby
giving complete range control of the effective minimum
position.
NOTE: For complete economizer control, the user can make
the economizer inactive by unplugging the enthalpy switch
connection.
CONTROLS OPERATION
Modes —
chy of command structure as defined by three essential elements: the System mode, the HVAC mode and the Control
mode. The System mode is the top level mode that defines three
essential states for the control system: OFF, RUN and TEST.
The HVAC mode is the functional level underneath the
System mode which further defines the operation of the
control.
The Control mode is essentially the control type of the unit
(Configuration
the control looks to establish a cooling or heating mode.
Furthermore, there are a number of modes which operate
concurrently when the unit is running. The operating modes of
the control are located at the local displays under OperatingModes. See Table 24.
The ComfortLink controls operate under a hierar-
UNITC.TYP). This defines from where
Currently Occupied (
OCC) — This variable displays the cur-
rent occupancy state of the unit.
Timed Override in Effect (
T. OV R) — This variable displays
if the state of occupancy is currently occupied due to an
override.
DCV Resetting Minimum Position (
DCV) — This variable
displays if the economizer position has been lowered from its
maximum vent position due to demand control ventilation.
Supply Air Reset (
SA.R) — This variable displays if the supply air set point that the rooftop is attempting to maintain is
currently being reset upwards. This applies to cooling only.
MODEMODES CONTROLLING UNIT
OCCCurrently OccupiedON/OFF MODEOCCP
T.OVR Timed Override in EffectON/OFF MODETOVR
DCVDCV Resetting Min PosON/OFF MODEADCV
SA.RSupply Air ResetON/OFF MODESARS
DMD.L Demand Limit in EffectON/OFF MODEDMLT
T.C.ST Temp.Compensated StartON/OFF MODETCST
IAQ.P IAQ Pre-Occ Purge ActiveON/OFF MODEIQPG
LINKLinkage Active — CCNON/OFF MODELINK
LOCK Mech.Cooling Locked OutON/OFF MODELOCK
H.NUM HVAC Mode Numerical Form numberMODEHVAC
Demand Limit in Effect (
DMD.L) — This variable displays
if the mechanical cooling capacity is currently being limited or
reduced by a third party.
Temperature Compensated Start (
T.C .S T) — This variable
displays if Heating or Cooling has been initiated before occupancy to pre-condition the space.
IAQ Pre-Occupancy Purge Active (
IAQ.P) — This variable
displays if the economizer is open and the fan is on to preventilate the building before occupancy.
Linkage Active CCN (
LINK) — This variable displays if a
linkage master in a zoning system has established “linkage”
with this air source (rooftop).
Mechanical Cooling Locked Out (
LOCK) — This variable
displays if mechanical cooling is currently being locked out
due to low outside air temperature.
HVAC Mode Numerical Form (
H.NUM) — This is a numerical representation of the HVAC modes which may be read via
a point read.
SYSTEM MODES (Operating Modes
System Mode Off
— When the system mode is OFF, all out-
SYS.M)
puts are to be shut down and no machine control is possible.
The following list displays the text assigned to the System
Mode when in the OFF mode and the conditions that may
cause this mode are checked in the following hierarchal order:
1. Wake up timer on a power reset.
(“Initializing System ...”)
2. System in the process of shutting down compressors and
waiting for timeguards to expire.
(“Shutting Down ...”)
3. Factory shut down (internal factory control level —
SHUTDOWN).
(“Factory Shut Down”)
4. Unit Stop (software application level variable that acts as
a hard shut down — Service Test
STOP).
(“Local Machine Stop”)
5. Fire Shut Down (fire shutdown condition based on the
Fire Shutdown Input (Inputs
FIREFSD).
(“Fire-Shutdown Mode”)
41
6. Emergency Stop, which is forced over the CCN through
the Emergency Stop Variable (EMSTOP).
(“CCN Emergency Stop”)
7. Start-up Delay.
(“Startup Delay = 0-900 secs”)
8. Service test ending transition timer.
(“Service Test Ending”)
— When the system mode is Test, the
control is limited to the Test mode and is controllable via the
local displays (Navigator™ display). The System Test modes
are Factory Test Enabled and Service Test Enabled. See the
Service Test section on page 29 for details on test control in this
mode.
1. Factory Test mode (“Factory test enabled”)
2. Service Test mode (“Service test enabled”)
System Mode Run
— When the system mode is Run, the software application in the control is free to run the HVAC control
routines by which cooling, heating, IAQ, etc., is possible.
There are two possible text displays for this mode, one is
normal run mode and the other occurs if one of the following
fire-smoke modes is present: smoke purge, pressurization or
evacuation.
1. Normal run time state (“Unit Operation Enabled”)
2. Fire-Smoke control mode (“Fire-Smoke Control”)
HVAC MODES (Operating Mode
HVAC) — The HVAC
mode is dependant on the system mode to allow it to further
determine the operational state of the rooftop unit. The actual
determination of an HVAC mode is based on a hierarchal
decision making process whereby certain overrides may interfere with normal temperature/humidity control. The decision
making process that determines the HVAC mode is shown in
Fig. 7 and Appendix E.
Each HVAC mode is described below. The HVAC mode
number is shown in the parenthesis after the mode.
HVAC Mode — STARTING UP (0)
— The unit is transi-
tioning from the OFF mode to a different mode.
HVAC Mode — DISABLED (1)
— The unit is shut down
due to a command software disable through the scrolling marquee, a CCN emergency stop command, a service test end, or a
control-type change delay.
HVAC Mode — SHUTTING DOWN (2)
— The unit is tran-
sitioning from a mode to the OFF mode.
HVAC Mode — SOFTSTOP REQUEST (3)
— The unit is
off due to a soft stop request from the control.
HVAC Mode — REM SW.DISABLE (4)
— The unit is off
due to the remote switch.
HVAC Mode — FAN STATUS FAIL (5)
— The unit is off
due to a supply fan status failure.
HVAC Mode — STATIC PRESSURE FAIL (6)
— The unit
is off due to failure of the static pressure sensor.
HVAC Mode — COMP.STUCK ON (7)
— The unit is shutdown because there is an indication that a compressor is running even though it has been commanded off.
HVAC Mode — OFF (8)
— The unit is off and no operating
modes are active.
HVAC Mode — TEST (9)
— The unit is in the self test mode
which is entered through the Service Test menu.
HVAC Mode — TEMPERING VENT (10)
— The economizer is at minimum vent position but the supply-air temperature has dropped below the tempering vent set point. Staged
gas heat, modulating gas heat, SCR electric heat, or hydronic
heat is used to temper the ventilation air.
HVAC Mode — TEMPERING LOCOOL (11)
— The economizer is at minimum vent position but the combination of the
outside-air temperature and the economizer position has
dropped the supply-air temperature below the tempering cool
set point. Staged gas heat, modulating gas heat, SCR electric
heat, or hydronic heat is used to temper the ventilation air.
HVAC Mode — TEMPERING HICOOL (12)
— The economizer is at minimum vent position but the combination of the
outside-air temperature and the economizer position has
dropped the supply-air temperature below the tempering cool
set point. Staged gas heat, modulating gas heat, SCR electric
heat, or hydronic heat is used to temper the ventilation air.
HVAC Mode — VENT (13)
— This is a normal operation
mode where no heating or cooling is required and outside air is
being delivered to the space to control IAQ levels.
HVAC Mode — LOW COOL (14)
— This is a normal cool-
ing mode where a low cooling demand is present.
HVAC Mode — HIGH COOL (15)
— This is a normal cool-
ing mode where a high cooling demand is present.
HVAC Mode — LOW HEAT (16)
— The unit will be in low
heating demand mode using either gas, electric, or hydronic
heat.
HVAC Mode — HIGH HEAT (17)
— The unit will be in
high heating demand mode using gas, electric, or hydronic
heat.
HVAC Mode — UNOCC. FREE COOL (18)
— In this
mode the unit will operate in cooling but will be using the
economizer for free cooling. Entering this mode will depend on
the status of the outside air. The unit can be configured for outside air dry bulb changeover, differential dry bulb changeover,
outside air enthalpy changeover, differential enthalpy changeover, or a custom arrangement of enthalpy/dew point and dry
bulb. See the Economizer section for further details.
HVAC Mode — FIRE SHUT DOWN (19)
— The unit has
been stopped due to a fire shutdown input (FSD) from two or
more of the fire control modes, purge, evacuation, or pressurization.
HVAC Mode — PRESSURIZATION (20)
— The unit is in
the special fire pressurization mode where the supply fan is on,
the economizer damper is open and the power exhaust fans are
off. This mode is invoked by the Fire Pressurization (PRES) input which can be found in the INPUTFIRE submenu.
HVAC Mode — EVACUATION (21)
— The unit is in the
special Fire Evacuation mode where the supply fan is off, the
economizer damper is closed and the power exhaust fans are
on. This mode is invoked by the Fire Evacuation (EVAC) input
which can be found in the INPUTFIRE submenu.
HVAC Mode — SMOKE PURGE (22)
— The unit is in the
special Fire Purge mode where the supply fan is on, the economizer damper is open and the power exhaust fans are on. This
mode is invoked by the Fire Evacuation (PURG) input which
can be found in the INPUTFIRE submenu.
HVAC Mode — DEHUMIDIFICATION (23)
operating in the Dehumidification mode. On units configured
for Humidi-MiZer
— The unit is operating in
Reheat mode. On units configured for Humidi-MiZer operation, this is the Humidi-MiZer reheat mode.
42
System Mode =
Fig. 7 — Mode Selection
OFF?
Yes
Inputs -> FIRE ->
FSD in alar m?
No
System
Mode
No
HVAC Mode = OFF
(Disabled)
Fire-
Smoke
Control
Unit not in facto ry
test AND fire-smoke
control mode is
alarming?
Yes
Inputs -> FIRE ->
PRES in alarm?
No
NoNo
Inputs -> FIRE ->
EVAC in alarm?
Yes
HVAC Mode = OF F
(Fire Shutdown)
Exceptions
Config->UNIT->
C.TYP changed
while unit running?
15-second delay
HVAC Mode = OF F
(Disabled)
Config->SP-> SP.CF
HVAC Mode = OFF
Yes
HVAC Mode = OF F
(Pressurization)
No
No
2
OR
= 1
and static pressure
sensor has failed
YesYesYesYesYesYes
(Static Pres. Fail)
System Mode =
TEST?
HVAC Mode = TEST
Config->UNI T->
SFS.M=1 OR 2 AND
Config->UNI T->
SFS.S=YES?
and supply fan
has failed
HVAC Mode = OFF
(Fan Status Fail)
No
No
HVAC Mode = OFF
(Plenum Pressure Trip)
Service Test ->
S.STP = YES?
HVAC Mode = SoftSt op
Request
Config->BP- >
AND
BP.CF=5
There is a plenum
pressure switch
error
NoNoNoNo
Config->UNIT->
NoNoNo
RM.CF =2 AN D
Inputs->GEN.I->
REMT = ON
HVAC Mode = OFF
(Rem. Sw. Disable)
Unit just wa king up
from power reset?
HVAC Mode = OF F
(Starting Up)
Yes
HVAC Mode = OF F
(Evacuation)
HVAC Mode = Shutting
HVAC Mode = OF F
(Config ->HEAT->
HT.TY= 4 OR Config ->
DEHU->D.SEL=1) AND
(Inputs ->GEN.I->
FRZ.S=ALRM?)
HVAC Mode = Fr eeze
Stat Trip
Unit shutting down?
Down
YesYesYesYesYes
(Purge)
Compress or
contactor welded
on?
HVAC Mode = Comp .
Stuck On
Unit control free to select
normal heating/cooling
HVAC mode
Unit
control free
to choose
HVAC
Mode
HVAC Mode = OFF
HVAC Mode =
Tempering Vent
HVAC Mode =
Tempering LoCool
HVAC Mode =
Tempering HiCool
HVAC Mode = Re- Heat
HVAC Mode =
Dehumidification
43
HVAC Mode = Vent
HVAC Mode = Low Cool
HVAC Mode = High Cool
HVAC Mode = Low He at
HVAC Mode = High Heat
HVAC Mode = Un occ.
Free Cool
HVAC Mode — FREEZESTAT TRIP (25)
— If the freezestat trips, the unit enters the Freezestat Trip HVAC mode. The
supply fan will run, the hydronic heat valve will be wide open,
and the economizer damper will be closed.
HVAC Mode — PLEN.PRESS.FAIL (26)
— The unit is off
due to a failure of the plenum pressure switch.
HVAC Mode — RCB COMM FAILURE (27)
— The unit is
off due to a Rooftop Control Board (RCB) communication failure.
HVAC Mode — SUPPLY VFD FAULT (28)
— The unit is
off due to a supply fan VFD fault or supply fan VFD communications loss.
Unit Configuration — There is a sub-menu under the
Configuration mode of the local display entitled UNIT. This
sub-menu contains an assortment of items that most of which
are relative to other particular sub-sections of this control manual. This section will define all of these configurations here for
easy reference. The sub-menu which contains these configurations is located at the local display under Configura-
tion
UNIT. See Table 25.
Machine Control Type (
fines the technique and control source responsible for selecting
a cooling mode and in determining the method by which compressors are staged.
The types possible will now be defined:
• C.TYP = 1 (VAV-RAT) and C.TYP = 2 ( VAV- S P T )
Both of these configurations refer to standard VAV operation. If the control is occupied, the supply fan is run
continuously and return-air temperature will be used for
both in the determination of the selection of a cooling
mode. VAV-SPT differs only in that during the unoccupied period, space temperature will be used to "kick
start" the fan for 10 minutes before the return-air temperature is allowed to call out any mode.
• C.TYP = 3 (TSTAT - MULTI )
This configuration will force the control to monitor the
thermostat inputs to make a determination of mode. But
unlike traditional 2-stage thermostat control the unit is
allowed to use multiple stages of cooling control and perform VAV style operation. Essentially the control will be
able to call out a LOW COOL or a HIGH COOL mode
and maintain a low or high cool supply air set point.
C.TYP) — This configuration de-
Table 25 — Unit Configuration
• C.TYP = 4 (SPT - MULTI )
This configuration will force the control to monitor a
space temperature sensor to make a determination of
mode. But unlike traditional 2-stage space temperature
control, the unit is allowed to use multiple stages of cooling control and perform VAV style operation. Essentially
the control will be able to call out a LOW COOL or a
HIGH COOL mode and maintain a low or high cool supply air set point.
Unit Size (75-150) (
SIZE) — There are several available tonnages for the N Series control. Make sure this configuration
matches the size called out by the model number of the unit.
This is important as the cooling stage tables are directly determined based on the SIZE configuration.
Fan Mode (
CV.FN) (0= Auto, 1= Cont) — This Fan Mode
configuration can be used for machine control types (Configu-
ration
UNITC.TYP) 3, 4, 5 and 6.
The Fan Mode variable establishes the operating sequence
for the supply fan during occupied periods. When set to 1 =
Continuous, the fan will operate continuously during occupied
periods.
When set to 0 = Automatic, the fan will run only during a
heating or cooling mode.
Remote Switch Configutation (
RM.CF) — The remote
switch input is connected to TB201 terminals 1 and 2. This
switch can be used for several remote control functions. Please
refer to the Remote Control Switch Input section on page 96
for details on its use and operation.
CEM Module Installed (
CEM) — This configuration instructs the control to communicate with the Controls Expansion Module (CEM) module over the local equipment network
(LEN) when set to YES. When the unit is configured for certain sensors and configs, this option will be set to YES automatically.
The sensors and configurations that automatically turn on
this board are:
Configuration
UNITSENSSRH.S = Enable (Space
Relative Humidity Sensor Enable)
Configuration
UNITSENSRRH.S = Enable (Re-
turn Air Relative Humidity Sensor Enable)
Configuration
UNITSENSMRH.S = Enable
(Mixed Air Relative Humidity Sensor Enable)
ITEMEXPANSIONRANGEUNITSCCN POINTDEFAULTS
UNITUNIT CONFIGURATION
C.TYPMachine Control Type1 to 4CTRLTYPE3
SIZEUnit Size (75-150)75 to 150UNITSIZE75
FN.MDFan Mode (0=Auto, 1=Cont)0 to 1FAN_MODE1
RM.CFRemote Switch Config0 to 3RMTINCFG0
CEMCEM Module InstalledNo/YesCEM_BRDNo
LQ.SNLiquid Sensors InstalledNo/YesLQ_SENSNo
PW.MNPower Monitor InstalledNo/YesPWR_MONNo
VFD.BVFD Bypass Enable?No/YesVFD_BYENNo
UVC.LUV-C Lamp Config?0 to 2UVCL_CFG0
TSC.CTemp.Cmp.Strt.Cool Factr0 to 60MinutesTCSTCOOL0
TSC.HTemp.Cmp.Strt.Heat Factr0 to 60MinutesTCSTHEAT0
SFS.SFan Fail Shuts Down UnitNo/YesSFS_SHUTNo
SFS.MFan Stat Monitoring Type0 to 2 SFS_MON0
VAV.SVAV Unocc.Fan Retry Time0 to 720MinutesSAMPMINS50
MAT.SMAT Calc Config0 to 2MAT_SEL1
MAT.RReset MAT Table Entries?No/YesMATRESETNo
MAT.DMAT Outside Air Default0 to 100%MATOADOS20
ALTIAltitude……..in feet:–1000 to 60000ALTITUDE0
DLAYStar tup Delay Time0 to 900SecondsDELAY0
AUX.RAuxiliary Relay Config0 to 3AUXRELAY0
SENSINPUT SENSOR CONFIG
SPT.SSpace Temp SensorDisable/EnableSPTSENSDisable
SP.O.SSpace Temp Offset SensorDisable/EnableSPTOSENSDisable
SP.O.RSpace Temp Offset Range1 to 10SPTO_RNG5
SRH.SSpace Air RH SensorDisable/EnableSPRHSENSDisable
RRH.SReturn Air RH SensorDisable/EnableRARHSENSDisable
MRH.SMixed Air RH SensorDisable/EnableMARHSENSDisable
ter Status is not disabled or schedule)
Liquid Sensors Installed (
structs the control to read the liquid temperature thermistors
and pressure transducers on A and B refrigeration circuits.
Power Monitor Installed (
structs the control to monitor the power status input.
VFD Bypass Enable (
the control to enable the EXB in order to use the supply fan relay (SFBYRLY) and ret/exh bypass relay (PEBRLY) outputs.
UV-C Lamp Configuration (
controls the enabling of the UV-C lamps to 0) none, 1) enabled,
2) enabled with status feedback.
Temperature Compensation Start Cooling Factor (
— This factor is used in the equation of the Temperature Compensated Start Time Bias for cooling. Refer to the Temperature
Compensated Start section for more information. A setting of
0 minutes indicates Temperature Compensated Start in Cooling is not permitted.
Temperature Compensated Start Heating Factor (
— This factor is used in the equation of the Temperature Compensated Start Time Bias for heating. Refer to the Temperature
Compensated Start section for more information. A setting of
0 minutes indicates Temperature Compensated Start in Heating
is not permitted.
Fan Fail Shuts Down Unit (
will allow whether the unit should shut down on a supply fan
status fail or simply alert the condition and continue to run.
YES – Shut down the unit if supply fan status monitoring fails
and send out an alarm
NO – Do not shut down the unit if supply fan status monitoring fails but send out an alert.
Fan Status Monitoring Type (
selects the type of fan status monitoring to be performed.
0 – NONE – No switch or monitoring
1 – SWITCH – Use of the fan status switch
2 – SP RISE – Monitoring of the supply duct pressure.
SP
SP
BP
BP
SP.RS = 1 (Static Pressure Reset us-
SP.RS = 4 (Static Pressure Reset us-
ECONCFM.COCF.S = Enable (Out-
EDT.RRES.S = Enable (4-20 ma Sup-
ECONORH.S = Enable (Outside Air
IAQDEHUD.SEN = 3 (DISCR.IN-
DMD.LDM.L.S = 1 (2 SWITCH-
DMD.LDM.L.S = 2 (4-20MA
IAQAQ.CFIQ.I.C = 1 (IAQ DIS-
IAQAQ.CFIQ.I.C = 2 (IAQ
IAQAQ.CFOQ.A.C = 1 (OAQ
IAQAQ.CFOQ.A.C = 2 (4-20 NO
IAQFLTCMFL.S = 1,3,4,5 (Main
IAQFLTCPFL.S = 1,3,4,5 (Post Fil-
LQ.SN) — This configuration in-
PW.MN) — This configuration in-
VFD.B) — This configuration instructs
UVC.L) — This configuration
TCS.C
TSC.H
SFS.S) — This configuration
SFS.M) — This configuration
VAV Unoccupied Fan Retry Time (
trol types 1 and 2 (VAV-RAT,VAV-SPT) include a process for
sampling the return-air temperature during unoccupied periods
to prove a valid demand for heating or cooling before initiating
an unoccupied heating or cooling mode. If the sampling routine runs but concludes a valid demand condition does not exist, the sampling process will not be permitted for the period of
time defined by this configuration. Reducing this value allows
a more frequent re-sampling process. Setting this value to zero
will prevent any sampling sequence.
MAT Calc Config (
user three options in the processing of the mixed-air temperature (MAT) calculation:
• MAT.S = 0
The control will not attempt to learn MAT over time. The
control will simply calculate MAT based on the position
of the economizer, outside and return air temperature,
linearly.
• MAT.S = 1
The control will attempt to learn MAT over time. Any
time the system is in a vent mode and the economizer
stays at a particular position for long enough, MAT =
EDT. Using this, the control has an internal table
whereby he can more closely zoom in on the true MAT
value.
• MAT.S = 2
The control will stop learning and use whatever the control has already learned. This would infer that the control
spent a part of its life at MAT.S = 1. This might be useful
to a commissioner of a system who first sets MAT.S = 1,
then might go into the service test mode, turn on the fan
and open the economizer to a static position for a little
more than 5 minutes and then move to several positions
to repeat the same (20%,40%,60%,80%). The only stipulation to this "commissioning" is that it is important that
the difference between return and outside temperature be
greater than 5 degrees. (The greater the delta, the better.)
When done, set MAT.S = 2 and the system has been
"learned" forever.
Reset MAT Table Entries? (
allows the user to reset the internally stored MAT "learned"
configuration entities back to their default values. The defaults
are set to a linear relationship between the economizer damper
)
)
position and OAT and RAT in the calculation of MAT.
Altitude.......in feet: (
clude a barometric pressure sensor to thoroughly define the calculation of enthalpy and CFM, the control does include an altitude parameter which will serve to set up a "mean" barometric
pressure for use to calculate with. The effect of barometric
pressure in these calculations is not great, but could have an effect depending on the installed elevation of the unit. Basically,
if the rooftop is installed at a particularly high altitude and enthalpy or CFM are being calculated, set this configuration to
the current elevation of the installed rooftop.
Start Up Delay Time (
from operating after a power reset. The configuration may be
adjusted from 0 to 900 seconds of delay.
Auxiliary Relay Output Configuration (
configuration allows the user to configure the function of the
auxiliary relay output. The output is 1.4 vac, 5 va maximum.
The configuration can be set from 0 to 3. If AUX.R is set to 0,
the auxiliary relay contact will be energized during an alarm.
The output can be used to turn on an indicator light or sound an
alarm in a mechanical room. If AUX.R is set to 1, the auxiliary
relay will energize when the controls determine dehumidification/reheat is needed. The relay would be wired to a third party
dehumidification/reheat device and would energize the device
when needed. If AUX.R is set to 2, the auxiliary relay will energize when the unit is in the occupied state. The relay could then
be used to control lighting or other functions that need to be on
MAT.S) — This configuration gives the
ALTI) — As the control does not in-
DLAY) — This option inhibits the unit
VAV.S) — Machine con-
MAT.R) — This configuration
AUX.R) — This
45
during the occupied state. If AUX.R is set to 3, the auxiliary relay will energize when the supply fan is energized (and, if
equipped with a VFD, the VFD output is not 0%). The default
is 0.
Space Temp Sensor (
SPT.S) — If a space temperature sensor
is installed (T55/T56), enable this configuration.
Space Temp Offset Sensor (
SP.O.S) — If a T56 sensor is installed with the space temperature offset slider, enable this configuration.
Space Temp Offset Range (
SP.O.R) — If a space temperature offset sensor is installed, it is possible to configure the
"sweep" range of the slider by adjusting this "range" configuration.
Space Air RH Sensor (
SRH.S) — If a space relative humidity
sensor is installed, enable this configuration.
Return RH Sensor (
RRH.S) — If a return air relative humidi-
ty sensor is installed, enable this configuration.
Mixed RH Sensor (
MRH.S) — If a mixed air relative humid-
ity sensor is installed, enable this configuration.
Cooling Control — The N Series ComfortLink controls
offer two basic control approaches to mechanical cooling:
multi-stage cooling (CV) and multiple stages of cooling (VAV).
In addition, the ComfortLink controls offer the ability to run
multiple stages of cooling for either a space temperature sensor
or thermostat by controlling the unit to either a low or high cool
supply air set point.
SETTING UP THE SYSTEM — The control type (Configu-
ration
UNITC.TYP) determines the selection of the type
of cooling control as well as the technique for selecting a cooling mode. Unit staging tables are shown in Appendix C.
NOTE: Whether a unit has a VFD or a supply fan installed for
static pressure control has no effect on configuration of the
machine control type (C.TYP). No matter what the control
type, it is possible to run the unit in either CV or VAV mode
provided there are enough stages to accommodate lower air
volumes for VAV operation. Refer to the section on static pressure control on page 69 for information on how to set up the
unit for the type of supply fan control desired.
Machine Control Type (
The most fundamental cooling control configuration is located
under Configuration
ITEMEXPANSIONRANGE
UNITUNIT CONFIGURATION
C.TYP Machine Control Type 1 - 4CTRLTYPE*
*This default is model number dependent.
This configuration defines the technique and control source
responsible for selecting a cooling mode and in determining the
method by which compressors are staged. The control types
are:
• C.TYP = 1 (VAV-RAT) and C.TYP = 2 ( VAV- S P T )
Both of these configurations refer to standard VAV opera-
tion. If the control is occupied, the supply fan is run continu-
ously and return-air temperature will be used for both in the
determination of the selection of a cooling mode. VAV-SPT
differs from VAV-RAT only in that during the unoccupied
period, space temperature will be used instead of return-air
temperature to start the fan for ten minutes before the re-
turn-air temperature is allowed to call out any mode.
• C.TYP = 3 (TSTAT – MULTI)
This configuration will force the control to monitor the ther-
mostat inputs to make a determination of mode. Unlike tra-
ditional 2-stage thermostat control, the unit is allowed to use
multiple stages of cooling control and perform VAV style
ConfigurationUNITC.TYP) —
UNIT.
CCN
POINT
DEFAULTS
operation. The control will be able to call out a LOW
COOL or a HIGH COOL mode and maintain a low or high
cool supply air set point.
• C.TYP = 4 (SPT – MULTI)
This configuration will force the control to monitor a space
temperature sensor to make a determination of mode. Unlike traditional 2-stage space temperature control, the unit is
allowed to use multiple stages of cooling control and perform VAV style operation. The control will be able to call
out a LOW COOL or a HIGH COOL mode and maintain a
low or high cool supply air set point.
MACHINE DEPENDENT CONFIGURATIONS — Some
configurations are linked to the physical unit and must not be
changed. The configurations are provided in case a field
replacement of a board occurs and the settings are not
preserved by the download process of the new software. The
following configurations apply to all machine control types
(C.TYP). These configurations are located at the local display
under Configuration
Unit Size (SIZE) — There are 6 unit sizes (tons) for the N Se-
ries control. Make sure this configuration matches the size
called out by the model number of the unit. This is important as
the cooling stage tables are directly determined based on the
SIZE configuration.
EDT Reset Configuration (
RS.CF) — This configuration ap-
plies to several machine control types (Configura-
tion
UNITC.TYP = 1,2,3, and 4). See Table 28.
• 0 = NO RESET
No supply air reset is in effect
•1 = SPT RESET
Space temperature will be used as the reset control variable
along with both RTIO and LIMT in the calculation of the
final amount of reset to be applied (Inputs
SA.S.R).
RSET
• 2 = RAT RESET
Return-air temperature will be used as the reset control vari-
able along with both RTIO and LIMT in the calculation of
the final amount of reset to be applied (Inputs
RSET
SA.S.R).
• 3 = 3RD PARTY RESET
The reset value is determined by a 4 to 20 mA third party
input. An input of 4 mA would correspond to 0º F reset. An
input of 20 mA would correspond to 20º F reset. Configuring the control for this option will cause RES.S to become
enabled automatically with the CEM board. To avoid
alarms make sure the CEM board and third party input are
connected first before enabling this option.
Reset Ratio (
RTIO) — This configuration is used when
RS.CF is set to 1 or 2. For every degree that the controlling
temperature (space/return) falls below the occupied cooling set
point (OCSP), the calculated value of the supply air reset will
rise by the number of degrees as specified by this parameter.
Reset Limit (
LIMT) — This configuration is used when
RS.CF is set to 1 or 2. This configuration places a clamp on the
amount of supply air reset that can be applied.
EDT 4-20 mA Reset Input (
automatically enabled when Configuration
RES.S) — This configuration is
EDT.R
RS.CF is set to 3 (third party reset).
46
COOLING CONFIGURATION — Relevant configurations for
mechanical cooling are located at the local display under
Configuration
Enable Compressor A1 (
COOL. See Table 29.
A1.EN) — This configuration is
used to disable the A1 compressor in case of failure for size 75
to 150 units.
Enable Compressor A2 (
A2.EN) — This configuration is
used to disable the A2 compressor in case of failure for size 75
to 150 units.
Enable Compressor A3 (
A3.EN) — This configuration is
used to disable the A3 compressor in case of failure for size 90
and 100 units. It is always disabled for size 75 units.
Enable Compressor A4 (
A4.EN) — This configuration is
used to disable the A4 compressor in case of failure for size
120 to 150 units. It is always disabled for size 75 to 105 units.
Enable Compressor B1 (
B1.EN) — This configuration is
used to disable the B1 compressor in case of failure for size 75
to 150 units.
Enable Compressor B2 (
B2.EN) — This configuration is
used to disable the B2 compressor in case of failure for size 75
to 150 units.
Enable Compressor B3 (
B3.EN) — This configuration is
used to disable the B3 compressor in case of failure for size 75
to 150 units.
Enable Compressor B4 (
B4.EN) — This configuration is
used to disable the B4 compressor in case of failure for size
120 to 150 units. It is always disabled for size 75 to 105 units.
CSB A1 Feedback Alarm (
CS.A1) — This configuration is
used to enable or disable the compressor A1 feedback alarm.
This configuration must be enabled whenever A1.EN is enabled.
CSB A2 Feedback Alarm (
CS.A2) — This configuration is
used to enable or disable the compressor A2 feedback alarm.
This configuration must be enabled whenever A2.EN is enabled.
CSB A3 Feedback Alarm (
CS.A3) — This configuration is
used to enable or disable the compressor A3 feedback alarm.
This configuration must be enabled whenever A3.EN is enabled.
CSB A4 Feedback Alarm (
CS.A4) — This configuration is
used to enable or disable the compressor A4 feedback alarm.
This configuration must be enabled whenever A4.EN is enabled.
CSB B1 Feedback Alarm (
CS.B1) — This configuration is
used to enable or disable the compressor B1 feedback alarm.
This configuration must be enabled whenever B1.EN is enabled.
CSB B2 Feedback Alarm (
CS.B2) — This configuration is
used to enable or disable the compressor B2 feedback alarm.
This configuration must be enabled whenever B2.EN is enabled.
CSB B3 Feedback Alarm (
CS.B3) — This configuration is
used to enable or disable the compressor B3 feedback alarm.
This configuration must be enabled whenever B3.EN is enabled.
CSB B4 Feedback Alarm (
CS.B4) — This configuration is
used to enable or disable the compressor B4 feedback alarm.
This configuration must be enabled whenever B4.EN is enabled.
Capacity Threshold Adjust (
Z.GN) — This configuration
provides an adjustment to the SUMZ Cooling Algorithm for
capacity control. The configuration affects the cycling rate of
the cooling stages by raising or lowering the threshold that demand must build to in order to add or subtract a stage of
cooling.
Normally this configuration should not require any tuning
or adjustment. If there is an application where the unit may be
significantly oversized and there are indications of high compressor cycles, then the Capacity Threshold Adjust (Z.GN) can
be used to adjust the overall logic gain. Normally this is set to
1.0, but it can be adjusted from 0.1 to 10. As the value of Z.GN
is increased, the cycling of cooling stages will be slowed.
Compressor Lockout Temperature (
MC.LO) — This configuration defines the outdoor air temperature below which mechanical cooling is locked out.
Lead/Lag Operation? (
LLAG) — This configuration selects
the type of lead/lag compressor operation for the unit. There
are 3 choices: automatic, circuit A, and circuit B.
0 = AUTOMATIC
If this configuration is set to “AUTOMATIC,” every time
cooling capacity drops to 0%, on the next call for cooling, the
control will start up the first compressor on the circuit that did
not start on the previous cooling cycle.
1 = CIRCUIT A
If this configuration is set to “CIRCUIT A,” every time
cooling capacity drops to 0%, a circuit A compressor is always
the first to start on the next call for cooling.
2 = CIRCUIT B
If this configuration is set to “CIRCUIT B,” every time
cooling capacity drops to 0%, a circuit B compressor is always
the first to start on the next call for cooling.
NOTE: If the unit is configured for a Digital Scroll (Configu-
ration
M.PIDDG.A1 = YES) or Minimum Load Valve
(Configuration
M.PIDMLV = ENABLE), then circuit A
is always the lead circuit regardless of the setting of this
configuration.
If the unit is configured for the Humidi-MiZer
®
adaptive
dehumidification system, then circuit B automatically becomes
the lead circuit when the unit enters into one of the HumidiMiZer modes (dehumidification or reheat). The unit will immediately start a circuit B compressor when a Humidi-MiZer
mode is initiated.
MotorMaster Control? (
M.M.) — The condenser fan staging
control for the unit is managed directly by the ComfortLink
controls. There is no physical Motormaster device in the standard unit. If the unit was ordered from the factory with low ambient control (Motormaster) option, nothing further needs to be
done. This configuration must be set to YES if an accessory
low ambient operation Motormaster V Control is installed on
the unit. Setting this configuration to YES alters the condenser
fan staging sequence to accommodate the Motormaster V control. See Head Pressure Control section, page 55, for more information.
Maximum Condenser Temp (
SCT.H) — This configuration
defines the saturated condensing temperature at which the head
pressure control routine will increase an outdoor fan stage. The
saturated condensing temperature of either running circuit rising above this temperature will increase a fan stage. If the outdoor-air temperature is greater than 72 F, then no outdoor fan
staging will occur, and the outdoor fan stage will default to the
maximum stage.
Minimum Condenser Temp (
SCT.L) — This configuration
defines the saturated condensing temperature at which the head
pressure control routine will decrease an outdoor fan stage. The
saturated condensing temperature of both running circuits decreasing below this temperature will decrease a fan stage. If the
outdoor-air temperature is greater than 72 F no outdoor fan
staging will occur, and the outdoor fan stage will default to the
maximum stage.
A1 is Digital Scroll (
DG.A1) — This configuration instructs
the unit controls as to whether the A1 compressor is a digital
scroll or regular scroll compressor. If set to YES, the
47
compressor will be controlled by the compressor staging routine and SUMZ Cooling Algorithm.
A1 Min Digital Capacity (
MC.A1) — This configuration defines the minimum capacity the digital scroll compressor is allowed to modulate to. The digital scroll compressor modulation range will be limited from MC.A1 to 100%.
Dig Scroll Adjust Delta (
DS.AP) — This configuration defines the maximum capacity the digital scroll will be allowed to
change per request by the SUMZ Cooling Algorithm.
Dig Scroll Adjust Delay (
DS.AD) — This configuration defines the time delay in seconds between digital scroll capacity
adjustments.
Dig Scroll Reduce Delta (
DS.RP) — This configuration defines the maximum capacity the digital scroll will be allowed to
decrease per request by the SUMZ Cooling Algorithm when
OAT is greater than Configuration
M.PIDDS.RO. This
ramped reduction is only imposed on a decrease in digital
scroll capacity. An increase in capacity will continue to follow
the value defined by Configuration
Dig Scroll Reduce Delay (
M.PIDDS.AP.
DS.RD) — This configuration de-
fines the time delay, in seconds, between digital scroll capacity
reduction adjustments when OAT is greater than Configura-
tion
M.PIDDS.RO. This ramped reduction is only im-
posed on a decrease in digital scroll capacity. An increase in capacity will continue to follow the value defined by Configura-
tion
M.PIDDS.AD.
Dig Scroll Reduction OAT (
DS.RO)
— Under certain operating conditions, a sharp decrease in digital scroll capacity can result in unstable unit operation. This configuration defines the
outdoor air temperature above which a reduced capacity (
figuration
tion
M.PIDDS.RP
M.PIDDS.RD
) and time delay (
) will be imposed on a digital scroll
Con-
Configura-
capacity reduction. This ramped reduction is only imposed on a
Table 27 — Setpoints
decrease in digital scroll capacity. An increase in capacity will
continue to follow the values defined by
tionM.PIDDS.AP
and
ConfigurationM.PIDDS.AD
Configura-
Dig Scroll Max Only OAT (DS.MO) — This configuration
defines the outdoor-air temperature above which the digital
scroll will not be allowed to modulate. The digital scroll will be
locked at 100% above this outdoor-air temperature.
Min Load Valve Enable (
MLV) — This configuration instructs the control as to whether a minimum load (hot gas bypass) valve has been installed and will be controlled by the
compressor staging routine.
High SST Alert Delay Time (
H.SST) — This option allows
the low saturated suction temperature alert timing delay to be
adjusted.
Reverse Rotation Verified? (
RR.VF) — This configuration is
used to enable or disable the compressor reverse rotation
detection algorithm. This algorithm performs a check for correct compressor rotation upon power up of the unit. The method for detecting correct rotation is based on the assumption that
there will be a drop in suction pressure upon a compressor start
if it is rotating in the correct direction.
A test is made once, on power up, for suction pressure
change on the first compressor of the first circuit to start.
Reverse rotation is determined by measuring suction pres-
sure at 3 points in time:
• 5 seconds prior to compressor start.
• At the instant the compressor starts.
• 5 seconds after the compressor starts.
The rate of suction pressure change from 5 seconds prior to
compressor start to compressor start (rate prior) is compared to
the rate of suction pressure change from compressor start to 5
seconds after compressor start (rate after).
.
ITEMEXPANSIONRANGEUNITSCCN POINTDEFAULT
OHSPOccupied Heat Setpoint40-99dFOHSP68
OCSPOccupied Cool Setpoint40-99dFOCSP75
UHSPUnoccupied Heat Setpoint40-99dFUHSP55
UCSPUnoccupied Cool Setpoint40-110dFUCSP90
GAPHeat-Cool Setpoint Gap2-10deltaFHCSP_GAP5
V. C. O NVAV Occ. Cool On Delta0-25deltaFVAVOCON3.5
V. C. O FVAV Occ. Cool Off Delta1-25deltaFVAVOCOFF2
SASPSupply Air Setpoint45-75dFSASP55
SA.HISupply Air Setpoint Hi45-75dFSASP_HI55
SA.LOSupply Air Setpoint Lo45-75dFSASP_LO60
SA.HTHeating Supply Air Setpt90-145dFSASPHEAT85
T.P RGTempering Purge SASP–20-80dFTEMPPURG50
T.C LTempering in Cool SASP5-75dFTEMPCOOL5
T.V.OCTempering Vent Occ SASP–20-80dFTEMPVOCC65
T.V.UNTempering Vent Unocc. SASP–20-80dFTEMPVUNC50
If (rate after) is less than (rate prior minus 1.25), alarm
A140 is generated. This alarm will disable mechanical cooling
and will require a manual reset.
It is important to note that in Service Test mode reverse rotation is checked on every compressor start.
Once it has been verified that power to the unit and compressors has been applied correctly and the compressors start
up normally, this configuration can be set to YES to disable the
reverse rotation check.
Use CSBs for HPS detect? (
CS.HP) — On units with multi-
ple compressors running on a circuit, the Current Sensor
49
Boards are used to help detect a High Pressure Switch trip. Set-
L.H.OF
DMDLHOFF
L.H.ON
DMDLHON
V.C. ON
VAVOCON
V.C. OF
VAVOCOFF
OHSP
Fig. 8 —VAV Occupied Period Trip Logic
a48-8414
ting this configuration to NO disables this additional High
Pressure switch trip detection.
COOL MODE SELECTION PROCESS — The N Series
ComfortLink controls offer three distinct methods by which
they may select a cooling mode.
1. Thermostat (C.TYP=3): The thermostat does not depend
upon the state of occupancy or temperature and the
modes are called out directly by the discrete inputs (In-
puts
STATY1 and Y2).
2. VAV cooling types (C.TYP=1 and 2) are called out
in the occupied period (Operating Modes
MODE
OCC=ON).
3. VAV cooling types (C.TYP=1 and 2) are called out in the
unoccupied period (Operating Modes
MODE
OCC=OFF). They are also used for space sensor control
types (C.TYP=4) in both the occupied and unoccupied
periods.
This section is devoted to the process of cooling mode
determination for the three types outlined above.
VAV Cool Mode Selection during the Occupied Period
(C.TYP = 1,2 and Operating ModesMODEOCC =ON)
— There is no difference in the selection of a cooling mode for
either VAV-RAT or VAV-SPT in the occupied period. The actual
selection of a cool mode, for both control types, is based upon
the controlling return-air temperature (Te mp e ra t u re s
AIR.TCTRLR.TMP). Typically this is the same as the return air temperature thermistor (Te m pe r at u re s
AIR.T RAT)
except when under CCN Linkage.
Cool Mode Determination — If the machine control type
(Configuration
UNITC.TYP) = 1 (VAV-RAT) or 2 (VAV-
SPT) and the control is occupied (Operating
Modes
MODEOCC=ON), then the unit will not follow
the occupied cooling set point (OCSP). Instead, the control
will follow two offsets in the determination of an occupied
VAV cooling mode (Setpoints
points
V. C . O F ), applying them to the low-heat off trip point
V. C . O N and Set-
and comparing the resulting temperature to the controlling
return temperature (R.TMP).
The Setpoints
Setpoints
V. C . O N (VAV cool mode on offset) and
V. C . O F (VAV cool mode off offset) offsets are
used in conjunction with the low heat mode off trip point to
determine when to bring cooling on and off and in enforcing a
true “vent” mode between heating and cooling. See Fig. 8. The
occupied cooling set point is not used in the determination of
the cool mode. The occupied cooling set point is used for supply air reset only.
The advantage of this offset technique is that the control can
safely enforce a vent mode without worrying about crossing set
points. Even more importantly, under CCN linkage, the
occupied heating set point may drift up and down and as such
this technique of using offsets ensures a guaranteed separation
in degrees F between the calling out of a heating or cooling
mode at all times.
VAV Occupied Cool Mode Evaluation Configuration — There
are VAV occupied cooling offsets under Setpoints.
NOTE: There is a sub-menu at the local display (Run Status
TRIP) that allows the user to see the exact trip points for
both the heating and cooling modes without having to calculate them. Refer to the Cool Mode Diagnostic Help section on
page 52 for more information.
To enter into a VAV Occupied Cool mode, the controlling
temperature must rise above [OHSP minus L.H.ON plus
L.H.OF plus V. C . O N ].
To exit out of a VAV Occupied Cool Mode, the controlling
temperature must fall below [OHSP minus L.H.ON plus
L.H.OF plus V. C . O N minus V. C . O F ].
NOTE: With vent mode, it is possible to exit out of a cooling
mode during the occupied period if the return-air temperature
drops low enough. When supply-air temperature reset is not
configured, this capability will work to prevent over-cooling
the space during the occupied period.
Supply Air Set Point Control and the Staging of Compressors
— Once the control has determined that a cooling mode is in
effect, the cooling control point (Run Status
CL.C.P) is calculated and is based upon the supply air set
VIEW
point (SetpointsSASP) plus any supply air reset being
applied (Inputs
RSETSA.S.R).
Refer to the SumZ Cooling Algorithm section on page 52
for a discussion of how the N Series ComfortLink controls
manage the staging of compressors to maintain supply-air
temperature.
VAV Cool Mode Selection during the Unoccupied Period
(C.TYP = 1,2; Operating ModesMODEOCC=OFF)
and Space Sensor Cool Mode Selection (C.TYP=4) — The
machine control types that utilize this technique of mode selection are:
• C.TYP = 1 (VAV-RAT) in the unoccupied period
• C.TYP = 2 (VAV-SPT) in the unoccupied period
• C.TYP = 4 (SPT-MULTI) in both the occupied and
unoccupied period
These particular control types operate differently than the
VAV types in the occupied mode in that there is both a LOW
COOL and a HIGH COOL mode. For both of these modes, the
control offers two independent set points, Setpoints
(for LOW COOL mode) and Setpoints
SA.HI (for HIGH
SA.LO
COOL mode).
The occupied and unoccupied cooling set points can be
found under Setpoints.
ITEMEXPANSION RANGE UNITS
OCSPOccupied
UCSPUnoccupied
Cool Setpoint
Cool Setpoint
55-80dFOCSP 75
75-95dFUCSP 90
CCN
POINT
DEFAULT
The heat/cool set point offsets are found under Configuration
BP
D.LV.T. See Table 30.
ITEMEXPANSION RANGE UNITS
V. C .O NVAV Oc c .
V. C .O FVAV Occ .
Cool On Delta
Cool Off Delta
0-25deltaF VAVOCON 3.5
1-25deltaF VAVOCOFF 2
CCN
POINT
DEFAULT
50
H.C.ON
L.C. OF/2
L.C.ON
Cooling Setpoint (OCSP,UCSP)
L.C. OF
Lo Cool End
Hi Cool End
Lo Cool Start
Hi Cool Start
Fig. 9 — Cool Mode Evaluation
Table 30 — Cool/Heat Set Point Offsets Configuration
MODEMODES CONTROLLING UNIT
OCCCurrently OccupiedON/OFF MODEOCCP
T.C.STTemp.Compensated StartON/OFF MODETCST
MODE.
referred to as comfort trending and the configurations of
interest are C.T.LV and C.T.TM.
Cool Trend Demand Level (C.T.LV) — This is the change in
demand that must occur within the time period specified by
C.T.TM in order to hold off a HIGH COOL mode regardless
of demand. This is not applicable to VAV control types
Cool Mode Evaluation Logic
— The first thing the control
determines is whether the unit is in the occupied mode (OCC)
or is in the temperature compensated start mode (T. C. S T). If
the unit is occupied or in temperature compensated start mode,
the occupied cooling set point (OCSP) is used. For all other
modes, the unoccupied cooling set point (UCSP) is used. For
further discussion and simplification this will be referred to as
the “cooling set point.” See Fig. 9.
(C.TYP=1 and 2) in the occupied period. As long as a LOW
COOL mode is making progress in cooling the space, the control will hold off on the HIGH COOL mode. This is especially
true for the space sensor machine control type (C.TYP) = 4,
because the unit may transition into the occupied mode and see
an immediate large cooling demand when the set points
change.
Cool Trend Time (C.T.TM) — This is the time period upon
which the cool trend demand level (
C.T.LV) operates and may
hold off staging or a HIGH COOL mode. This is not applicable to VAV control types (C.TYP=1 and 2) in the occupied
period. See the Cool Trend Demand Level section for more
details.
Timeguards— In addition to the set points and offsets which
determine the trip points for bringing on and bringing off cool
modes there is a timeguard which enforces a time delay
between the transitioning from a low cool to a high cool mode.
This time delay is 8 minutes. There is a timeguard which
enforces a time delay between the transitioning from a heat
mode to a cool mode. This time delay is 5 minutes.
Supply Air Set Point Control — Once the control has deter-
mined that a cooling mode is in effect, the cooling control
Demand Level Low Cool On Offset (L.C.ON) — This is the
cooling set point offset added to the cooling set point at which
point a Low Cool mode starts.
Demand Level High Cool On Offset (H.C.ON) — This is the
cooling set point offset added to the “cooling set point plus
L.C.ON” at which point a High Cool mode begins.
Demand Level Low Cool Off Offset (L.C.OF) — This is the
cooling set point offset subtracted from “cooling set point plus
L.C.ON” at which point a Low Cool mode ends.
NOTE: The “high cool end” trip point uses the “low cool off”
(L.C.OF) offset divided by 2.
To enter into a LOW COOL mode, the controlling tempera-
ture must rise above [the cooling set point plus L.C.ON.]
To enter into a HIGH COOL mode, the controlling temperature must rise above [the cooling set point plus L.C.ON plus
H.C.ON.]
To exit out of a LOW COOL mode, the controlling temperature must fall below [the cooling set point plus L.C.ON minus
L.C.OF.]
To exit out of a HIGH COOL mode, the controlling temperature must fall below [the cooling set point plus L.C.ON minus
L.C.OF/2.]
Comfort Trending — In addition to the set points and offsets
which determine the trip points for bringing on and bringing
off cool modes, there are 2 configurations which work to hold
off the transitioning from a low cool to a high cool mode if the
space is cooling down quickly enough. This technique is
point (Run Status
based upon either Setpoints
depending on whether a high or a low cooling mode is in
effect, respectively. In addition, if supply air reset is configured, it will also be added to the cooling control point.
Refer to the SumZ Cooling Algorithm section for a discussion of how the N Series ComfortLink controls manage supplyair temperature and the staging of compressors for these
control types.
C.TYP
= 3 (Thermostat Cool Mode Selection) — When a
thermostat type is selected, the decision making process involved in determining the mode is straightforward. Upon energizing the Y1 input only, the unit HVAC mode will be LOW
COOL. Upon the energizing of both Y1 and Y2 inputs, the unit
HVAC mode will be HIGH COOL. If just input G is energized
the unit HVAC mode will be VENT and the supply fan will
run.
Selecting the C.TYP = 3 (TSTAT – MULTI) control type
will cause the control to do the following:
• The control will read both the Configuration
SIZE and ConfigurationUNIT50.HZ configuration parameters to determine the number of cooling
stages and the pattern for each stage.
• An HVAC mode equal to LOW COOL will cause the
unit to select the Setpoints
to. An HVAC mode equal to HIGH COOL will cause the
unit to select the Setpoints
to. Supply air reset (if configured) will be added to either
the low or high cool set point.
VIEWCL.C.P) is calculated and is
SA.HI or SetpointsSA.LO,
SA.LO set point to control
SA.HI set point to control
UNIT
51
• The control will utilize the SumZ cooling algorithm and
control cooling to a supply air set point. See the section
for the SumZ Cooling Algorithm section for information
on controlling to a supply air set point and compressor
staging.
COOL MODE DIAGNOSTIC HELP — To quickly determine the current trip points for the cooling modes, the Run
Status sub-menu at the local display allows the user to view the
calculated start and stop points for both the cooling and heating
trip points. The following sub-menu can be found at the local
display under Run Status
The controlling temperature is “TEMP” and is in the middle
of the table for easy reference. The HVAC mode can also be
viewed at the bottom of the table.
For non-linkage applications and VAV control types
(C.TYP = 1 or 2), “TEMP” is the controlling return air temper-
ature (R.TMP). For space sensor control, “TEMP” is the controlling space temperature (S.TMP). For linkage applications,
“TEMP” is zone temperature: AOZT during occupied periods
and AZT during unoccupied periods.
SUMZ COOLING ALGORITHM — The SumZ cooling algorithm is an adaptive PID (proportional, integral, derivative)
which is used by the control whenever more than 2 stages of
cooling are present (C.TYP = 1,2,3, and 4). This section will describe its operation and define the pertinent parameters. It is generally not necessary to modify parameters in this section. The
information is presented primarily for reference and may be
helpful for troubleshooting complex operational problems.
The only configuration parameter for the SumZ algorithm is
located at the local display under Configura-
tion
COOLZ.GN. See Table 29.
Capacity Threshold Adjust (
Z.GN) — This configuration affects the cycling rate of the cooling stages by raising or lowering the threshold that capacity must build to in order to add or
subtract a stage of cooling.
The cooling algorithm’s run-time variables are located at
the local display under Run Status
Current Running Capacity (
COOL. See Table 32.
C.CAP) — This variable repre-
sents the amount of capacity currently running in percent.
Current Cool Stage (
CUR.S) —This variable represents the
cool stage currently running.
Requested Cool Stage (
REQ.S) —This variable represents
the requested cool stage. Cooling relay timeguards in place
may prevent the requested cool stage from matching the current cool stage.
Maximum Cool Stages (
MAX.S) —This variable is the max-
imum number of cooling stages the control is configured for
and capable of controlling.
Active Demand Limit (
DEM.L) —If demand limit is active,
this variable will represent the amount of capacity that the
control is currently limited to.
Capacity Load Factor (
SMZ) —This factor builds up or
down over time and is used as the means of adding or subtracting a cooling stage during run time. It is a normalized representation of the relationship between “Sum” and “Z”. The control
will add a stage when SMZ reaches 100 and decrease a stage
when SMZ equals -100.
Next Stage EDT Decrease (
ADD.R) —This variable repre-
sents (if adding a stage of cooling) how much the temperature
should drop in degrees depending on the R.PCT calculation
and exactly how much additional capacity is to be added.
ADD.R = R.PCT * (C.CAP — capacity after adding a cooling
stage)
For example: If R.PCT = 0.2 and the control would be
adding 20% cooling capacity by taking the next step up,
0.2 times 20 = 4 F (ADD.R)
Next Stage EDT Increase (
SUB.R) —This variable repre-
sents (if subtracting a stage of cooling) how much the temperature should rise in degrees depending on the R.PCT calculation
and exactly how much capacity is to be subtracted.
SUB.R = R.PCT * (C.CAP — capacity after subtracting a
cooling stage)
For Example: If R.PCT = 0.2 and the control would be subtracting 30% capacity by taking the next step down, 0.2 times
–30 = –6 F (SUB.R)
Rise Per Percent Capacity (
R.PCT) —This is a real time cal-
culation that represents the number of degrees of drop/rise
across the evaporator coil versus percent of current running
capacity.
R.PCT = (MAT – EDT)/ C.CAP
Cap Deadband Subtracting (
Y.MIN) — This is a control vari-
able used for Low Temp Override (L.TMP) and Slow Change
Override (SLOW).
Y.MIN = -SUB.R*0.4375
Cap Deadband Adding (
Y.PLU) —This is a control variable
used for High Temp Override (H.TMP) and Slow Change
Override (SLOW).
Y.PLU = -ADD.R*0.4375
Cap Threshold Subtracting (
Z.MIN) —This parameter is
used in the calculation of SMZ and is calculated as follows:
Z.MIN = Configuration
COOLZ.GN * (–10 + (4*
(–SUB.R))) * 0.6
Cap Threshold Adding (
Z.PLU) —This parameter is used in
the calculation of SMZ and is calculated as follows:
Z.PLU = Configuration
COOLZ.GN * (10 + (4*
(–ADD.R))) * 0.6
High Temp Cap Override (
H.TMP) —If stages of mechani-
cal cooling are on and the error is greater than twice Y. PL U,
and the rate of change of error is greater than 0.5F per minute,
then a stage of mechanical cooling will be added every 30 seconds. This override is intended to react to situations where the
load rapidly increases.
Low Temp Cap Override (
L.TMP) —If the error is less than
twice Y.MIN , and the rate of change of error is less than
–0.5F per minute, then a mechanical stage will be removed
every 30 seconds. This override is intended to quickly react to
situations where the load is rapidly reduced.
52
Table 32 — Run Status Cool Display
ITEMEXPANSIONRANGEUNITSCCN POINTWRITE STATUS
COOLCOOLING INFORMATION
C.CAPCurrent Running Capacity%CAPTOTAL
CUR.SCurrent Cool StageCOOL_STG
REQ.SRequested Cool StageCL_STAGE
MAX.SMaximum Cool StagesCLMAXSTG
DEM.LActive Demand Limit%DEM_LIMforcible
SUMZCOOL CAP. STAGE CONTROL
SMZCapacity Load Factor-100 – +100SMZ
ADD.RNext Stage EDT Decrease^FADDRISE
SUB.RNext Stage EDT Increase^FSUBRISE
R.PCTRise Per Percent CapacityRISE_PCT
Y.MINCap Deadband SubtractingY_MINUS
Y.PLUCap Deadband AddingY_PLUS
Z.MINCap Threshold SubtractingZ_MINUS
Z.PLUCap Threshold AddingZ_PLUS
H.TMPHigh Temp Cap OverrideHI_TEMP
L.TMPLow Temp Cap OverrideLOW_TEMP
PULLPull Down Cap OverridePULLDOWN
SLOWSlow Change Cap OverrideSLO_CHNG
HMZRHUMIDIMIZER
CAPCHumidimizer CapacityHMZRCAPC
C.EXVCondenser EXV PositionCOND_EXV
B.EXVBypass EXV PositionBYP_EXV
RHVHumidimizer 3-Way ValveHUM3WVAL
C.CPTCooling Control PointCOOLCPNT
EDTEvaporator Discharge TmpEDT
H.CPTHeating Control PointHEATCPNT
LATLeaving Air TemperatureLAT
EXVSEXVS INFORMATION
A1.EXCircuit A EXV 1 Position XV1APOSP
A2.EXCircuit A EXV 2 Position XV2APOSP
B1.EXCircuit B EXV 1 Position XV1BPOSP
B2.EXCircuit B EXV 2 Position XV2BPOSP
SH.A1Cir A EXV1 Superheat Tmp SH_A1
SH.A2Cir A EXV2 Superheat Tmp SH_A2
SH.B1Cir B EXV1 Superheat Tmp SH_B1
SH.B2Cir B EXV2 Superheat Tmp SH_B2
CTRLEXVS CONTROL INFORMATION
C.SHSEXV Superheat Ctrl SP SH_SP_CT
C.FLSEXV SH Flooding Ctrl SP FL_SP_CT
C.EXPEXV PID Ctrl Prop. Gain EXV_PG_C
C.EXTEXV Ctrl Integrat. Time EXV_TI_C
C.EXMCir Strt EXV Mn Ctrl PosEXCSMP_C
Pull Down Cap Override (
PULL) —If the error from set
point is above 4F, and the rate of change is less than –1F per
minute, then pulldown is in effect, and “SUM” is set to 0. This
keeps mechanical cooling stages from being added when the
error is very large, but there is no load in the space. Pulldown
for units is expected to rarely occur, but is included for the rare
situation when it is needed. Most likely pulldown will occur
when mechanical cooling first becomes available shortly after
the control goes into an occupied mode (after a warm unoccupied mode).
Slow Change Cap Override (
SLOW) —With a rooftop unit,
the design rise at 100% total unit capacity is generally around
30 F. For a unit with 4 stages, each stage represents about
7.5F of change to EDT. If stages could reliably be cycled at
very fast rates, the set point could be maintained very precisely.
Since it is not desirable to cycle compressors more than 6 cycles per hour, slow change override takes care of keeping the
PID under control when “relatively” close to set point.
Humidi-MiZer® Capacity
(CAPC) — This variable represents the total reheat capacity currently in use during a HumidiMiZer mode. A value of 100% indicates that all of the discharge gas is being bypassed around the condenser and into the
Humidi-MiZer dehumidification/reheat coil (maximum reheat). A value of 0% indicates that all of the flow is going
through the condenser before entering the Humidi-MiZer dehumidification/reheat coil (dehum/subcooling mode).
Condenser EXV Position
(C.EXV) — This variable repre-
sents the position of the condenser EXV (percent open).
Bypass EXV Position
(B.EXV) — This variable represents
the position of the bypass EXV (percent open).
Humidi-MiZer 3-Way Valve
(RHV) — This variable represents the position of the 3-way valve used to switch the unit
into and out of a Humidi-MiZer mode. A value of 0 indicates
that the unit is in a standard cooling mode. A value of 1 indicates that the unit has energized the 3-way valve and entered
into a Humidi-MiZer mode.
Cooling Control Point
(C.CPT) — Displays the current cooling control point (a target value for air temperature leaving the
evaporator coil location). During a Humidi-MiZer mode, this
variable will take on the value of the dehumidify cool set point
(Configuration
DEHUD.C.SP). Compressors will stage
up or down to meet this temperature.
Evaporator Discharge Temperature
(EDT) — Displays the
temperature measured between the evaporator coils and the
Humidi-MiZer dehumidification/reheat coil. Units configured
with Humidi-MiZer system have a thermistor grid installed between these two coils to provide the measurement. This temperature can also be read at Temperatures
Heating Control Point
(H.CPT) — Displays the current heat-
AIR.TCCT.
ing control point for Humidi-MiZer system. During a Reheat
mode, this temperature will be either an offset subtracted from
return air temperature (D.V.RA) or the Vent Reheat Set Point
(D.V.HT). During a Dehumidification mode, this temperature
will take on the value of the original cooling control point so
that the supply air is reheated just enough to meet the sensible
demand in the space. The Humidi-Mizer modulating valves
will adjust to meet this temperature set point.
Leaving Air Temperature
(LAT) — Displays the leaving air
temperature after the Humidi-MiZer reheat/dehumidification
coil.
53
SumZ Operation
— The SumZ algorithm is an adaptive PID
style of control. The PID (proportional, integral, derivative) is
programmed within the control and the relative speed of staging can only be influenced by the user through the adjustment
of the Z.GN configuration, described in the reference section.
The capacity control algorithm uses a modified PID algorithm,
with a self adjusting gain which compensates for varying conditions, including changing flow rates across the evaporator
coil.
Previous implementations of SumZ made static assumptions about the actual size of the next capacity jump up or
down. This control uses a “rise per percent capacity” technique
in the calculation of SumZ, instead of the previous “rise per
stage” method. For each jump, up or down in capacity, the
control will know beforehand the exact capacity change
brought on. Better overall staging control can be realized with
this technique.
SUM Calculation — The PID calculation of the “SUM” is
evaluated once every 80 seconds.
SUM = Error + “SUM last time through” + (3 * Error Rate)
Where:
SUM = the PID calculation
Error = EDT – Cooling Control Point
Error Rate = Error – “Error last time through”
NOTE: “Error” is clamped between –10 and +50 and “Error
rate” is clamped between –5 and +5.
This “SUM” will be compared against the “Z” calculations
in determining whether cooling stages should be added or
subtracted.
Z Calculation — For the “Z” calculation, the control attempts
to determine the entering and the leaving-air temperature of the
evaporator coil and based upon the difference between the two
during mechanical cooling, determines whether to add or
subtract a stage of cooling. This is the adaptive element.
The entering-air temperature is referred to as MAT
(mixed-air temperature) and the leaving-air temperature of the
evaporator coil is referred to as EDT (evaporator discharge
temperature). They are found at the local display under the
Temperatures
CTRL sub-menu.
The main elements to be calculated and used in the calculation of SumZ are:
1) the rise per percent capacity (R.PCT)
2) the amount of expected rise for the next cooling stage
addition
3) the amount of expected rise for the next cooling stage
subtraction
The calculation of “Z” requires two variables, Z.PLU used
when adding a stage and Z.MIN used when subtracting a stage.
Where:
Z.GN = configuration used to modify the threshold levels used
for staging (Configuration
COOLZ.GN)
ADD.R = R.PCT * (C.CAP – capacity after adding a cooling
stage)
SUB.R = R.PCT * (C.CAP – capacity after subtracting a cool-
ing stage)
Both of these terms, Z.PLU and Z.MIN, represent a threshold both positive and negative upon which the “SUM” calculation must build up to in order to cause the compressor to stage
up or down.
Comparing SUM and Z — The “SUM” calculation is compared against Z.PLU and Z.MIN.
• If “SUM” rises above Z.PLU, a cooling stage is added.
• If “SUM” falls below Z.MIN, a cooling stage is subtracted.
There is a variable called SMZ which is described in the
reference section and which can simplify the task of watching
the demand build up or down over time. It is calculated as
follows:
If SUM is positive: SMZ = 100*(SUM/Z.PLU)
If SUM is negative: SMZ = 100*(SUM/Z.MIN)
Mixed Air Temperature Calculation (MAT)
— The mixedair temperature is calculated and is a function of the economizer position. Additionally there are some calculations in the control which can zero in over time on the relationship of return
and outside air as a function of economizer position. There are
two configurations which relate to the calculation of “MAT.”
These configurations can be located at the local display under
MAT Calc Config (MAT.S) —This configuration gives the
user three options in the processing of the mixed-air temperature (MAT) calculation:
• MAT.S = 0
There will be no MAT calculation.
• MAT.S = 1
The control will attempt to learn MAT over time. Any time
the system is in a vent mode and the economizer stays at a
particular position for long enough, MAT = EDT. Using
this, the control has an internal table whereby it can more
closely determine the true MAT value.
• MAT.S = 2
The control will stop learning and use whatever the control
has already learned. Using this setting infers that the control
has spent some time set to MAT.S = 1.
First set MAT.S = 1. Then go into the Service Test mode,
turn on the fan and open the economizer to a static position for
5 minutes. Move to several positions (20%,40%,60%,80%). It
is important that the difference between return and outside
temperature be greater than 5 degrees. (The greater the delta,
the better). When done, set MAT.S = 2 and the system has been
commissioned.
Reset MAT Table Entries? (MAT.R) —This configuration
allows the user to reset the internally stored MAT learned
configuration data back to the default values. The defaults are
set to a linear relationship between the economizer damper
position and OAT and RAT in the calculation of MAT.
SumZ Overrides
— There are a number of overrides to the
SumZ algorithm which may add or subtract stages of cooling.
• High Temp Cap Override (H.TMP)
• Low Temp Cap Override (L.TMP)
• Pull Down Cap Override (PULL)
• Slow Change Cap Override (SLOW)
Economizer Trim Override
— The unit may drop stages of
cooling when the economizer is performing free cooling and
the configuration Configuration
ECONE.TRM is set to
Yes. The economizer controls to the same supply air set point
as mechanical cooling does for SumZ when E.TRM = Yes.
This allows for much tighter temperature control as well as cutting down on the cycling of compressors.
For a long cooling session where the outside-air temperature may drop over time, there may be a point at which the
economizer has closed down far enough were the unit could
54
remove a cooling stage and open up the economizer further to
make up the difference.
Mechanical Cooling Lockout (
ConfigurationCOOL
MC.LO) — This configuration allows a configurable outside-
air temperature set point below which mechanical cooling will
be completely locked out.
DEMAND LIMIT CONTROL — Demand Limit Control
may override the cooling algorithm and clamp or shed
cooling capacity during run time. The term Demand Limit
Control refers to the restriction of the machine capacity
to control the amount of power that a machine will use.
Demand limit control is intended to interface with an external
Loadshed Device either through CCN communications, external switches, or 4 to 20 mA input.
The control has the capability of loadshedding and limiting
in 3 ways:
• Two discrete inputs tied to configurable demand limit set
point percentages.
• An external 4 to 20 mA input that can reset capacity back
linearly to a set point percentage.
• CCN loadshed functionality.
NOTE: It is also possible to force the demand limit variable
(Run Status
COOLDEM.L).
To use Demand Limiting, select the type of demand limiting
to use. This is done with the Demand Limit Select configuration (Configuration
BP
DMD.LDM.L.S).
To view the current demand limiting currently in effect,
look at Run Status
COOLDEM.L.
The configurations associated with demand limiting can be
viewed at the local display at Configuration
BP
DMD.L.
See Table 33.
Demand Limit Select (
DM.L.S) — This configuration deter-
mines the type of demand limiting.
• 0 = NONE — Demand Limiting not configured.
• 1 = 2 SWITCHES — This will enable switch input
demand limiting using the switch inputs connected to the
CEM board. Connections should be made to TB202
terminals 1,2,3, and 4.
• 2 = 4 to 20 mA — This will enable the use of a remote 4
to 20 mA demand limit signal. The CEM module must
be used. The 4 to 20 mA signal must come from an externally sourced controller and should be connected to
TB202 terminals 10 and 11.
• 3 = CCN LOADSHED — This will allow for loadshed
and red lining through CCN communications.
Two-Switch Demand Limiting (DM.L.S = 1) — This type of
demand limiting utilizes two discrete inputs:
• Demand Limit Switch 1 Setpoint (D.L.S1) — Dmd Limit
Switch Setpoint 1 (0 to 100% total capacity)
• Demand Limit 2 Setpoint (D.L.S2) — Dmd Limit Switch
Setpoint 2 (0 to 100% total capacity)
The state of the discrete switch inputs can be found at the lo-
cal display:
Inputs
GEN.IDL.S1
Inputs
GEN.IDL.S2
The following table illustrates the demand limiting (Run
Status
COOLDEM.L) that will be in effect based on the
logic of the applied switches:
Switch StatusRun StatusCOOLDEM.L = 1
Inputs
GEN.IDL.S1 = OFF
Inputs
Inputs
InputsGEN.IDL.S2 = OFF
Inputs
Inputs
Inputs
Inputs
GEN.IDL.S2 = OFF
GEN.IDL.S1= ON
GEN.IDL.S1= ON
GEN.IDL.S2 = ON
GEN.IDL.S1= OFF
GEN.IDL.S2 = ON
100%
ConfigurationDMD.LD.L.S1
Configuration
Configuration
DMD.LD.L.S2
DMD.LD.L.S2
4-20 mA Demand Limiting (DM.L.S = 2) — If the unit has
been configured for 4 to 20 mA demand limiting, then the
Inputs
4-20DML.M value is used to determine the
amount of demand limiting in effect (Run Sta-
tus
COOLDEM.L). The Demand Limit at 20 mA
(D.L.20) configuration must be set. This is the configured
demand limit corresponding to a 20 mA input (0 to 100%).
The value of percentage reset is determined by a linear
interpolation from 0% to “D.L.20”% based on the Inputs
4-20DML.M input value.
The following examples illustrate the demand limiting
(Run Status
COOLDEM.L) that will be in effect based on
amount of current seen at the 4 to 20 mA input, DML.M.
CCN Loadshed Demand Limiting (DM.L.S = 3) — If the unit
has been configured for CCN Loadshed Demand Limiting,
then the demand limiting variable (Run Status
COOL
DEM.L) is controlled via CCN commands.
The relevant configurations for this type of demand limiting
are:
Loadshed Group Number (SH.NM) — CCN Loadshed Group
number
Loadshed Demand Delta (SH.DL) — CCN Loadshed
Demand Delta
Maximum Loadshed Time (SH.TM) — CCN Maximum
Loadshed time
The Loadshed Group Number (SH.NM) corresponds to
the loadshed supervisory device that resides elsewhere on the
CCN network and broadcasts loadshed and redline commands to its associated equipment parts. The SH.NM variable
will default to zero which is an invalid group number. This
allows the loadshed function to be disabled until configured.
Upon reception of a redline command, the machine will be
prevented from starting if it is not running. If it is running,
then DEM.L is set equal to the current running cooling capacity (Run Status
COOLC.CAP).
Upon reception of a loadshed command, the DEM.L variable is set to the current running cooling capacity (Run Status
COOLC.CAP) minus the configured Loadshed Demand
Delta (SH.DL).
A redline command or loadshed command will stay in
effect until a Cancel redline or Cancel loadshed command is
received, or until the configurable Maximum Loadshed time
(SH.TM) has elapsed.
HEAD PRESSURE CONTROL — Condenser head pressure
for the 48/50N Series is managed directly by the ComfortLink
controls. The controls are able to cycle up to 9 stages of outdoor
fans to maintain acceptable head pressure. Fan stages will be
turned on or off in reaction to discharge pressure sensors with
the pressure converted to the corresponding saturated condensing temperature.
An option to allow fan speed control (Motormaster
®
) on the
first stage is configured by setting Configura-
tion
COOLM.M = Yes.
There are five configurations provided for head pressure
control that can be found at the local display:
Configuration
Configuration
COOLM.M (MotorMaster enable)
M.PIDSCT.H (Maximum Condensing
Tem p)
Configuration
M.PIDSCT.L (Minimum Condensing
Tem p)
55
There are up to four outputs provided to control head
pressure:
Outputs
Outputs
Outputs
Outputs
Outputs
FA NSCDF.1 — Condenser Fan Output 1
FA NSCDF.2 — Condenser Fan Output 2
FA NSCDF.3 — Condenser Fan Output 3
FA NSCDF.4 — Condenser Fan Output 4
FA NSCDF.5 — Condenser Fan Output 5
The specific staging sequence for a unit depends on the 3
factors: the unit size (tonnage), which refrigeration circuits are
currently operating, and whether or not MotorMaster is en-
The condenser fan output controls outdoor fan contactors
and outdoor fans for each unit tonnage as shown in Fig. 10.
Each stage of fans is also shown. The ComfortLink controller
adds or subtracts stages of fans based on SCT.H and SCT.L.
When the SCT rises above SCT.H, a fan stage will be added.
The ComfortLink controller will continue to add a fan stage every 10 seconds thereafter if the SCT remains above SCT.H. If
SCT rises above 130 F, the controller will turn on the maximum fan stages for the unit. When the SCT drops below the
SCT.L, a fan stage will be subtracted. The ComfortLink con-
troller will continue to drop a fan stage every 2 minutes thereafter if the SCT remains below SCT.L.
High Ambient Pres tart (OAT ≥ 70 F) = Stage 6/7Stage 2OFC1,2,33OFM2,5,8
High Saturated Condensing Temp (SCT>130) = Stage 6/7Stage 3OFC1,3,44OFM2,3,7,8
Stage 4OFC1,2,3, 45OFM2,3,4,7,8
Stage down allowed if SCT<SCT_MINStage 5OFC1,3,56OFM1,2,4,6,8, 9
Stage up allowed if SCT_MAX<SCT<130Stage 6OFC1,2,3,4, 59OFM1, 2,3,4,5,6, 7,8,9
Current st age if SCT_MIN<SCT<SCT_MAX
Circuit A or B SCT or OAT
Circuit A or B SCT or OAT
Circuit A or B SCT or OAT
Allow Fan Staging if OAT < 70 F and:
Circu it A, M.M.=NO
Circuit B, M.M.=NO
Common, M.M.=NO
Circuit B, M.M.=YES
Common, M.M.=YES
Circu it A, M.M.=YES
Allow Fan Staging if OAT < 70 F and:
Circuit
Controlling Output
Logic
Comp A1, A2, A3, or A4 ON
Comp B1, B2, B3, or B4 ON
POWER
BOX
3
MM
2
9
MM
8
A4
A3
B2
B1
B3
1
7
6
5
4
B4
A2
A1
Fig. 13 — 150 Ton Unit Condenser Fan Staging Sequence
a48-8700
LEGEND
MM— Motormaster
OAT— Outdoor Air Temperature
OFC— Outdoor Fan Contactor
OFM— Outdoor Fan Motor
60
When a condenser fan output is common to both refrigeration circuits, in other words when the fan(s) will affect both circuit A and circuit B, the following logic is used: in order to add
a fan stage, the SCT of either circuit must be above SCT.H for
30 seconds and in order to subtract a stage, the SCT of both circuits must be below SCT.L for 30 seconds.
Whenever the outdoor ambient temperature (OAT), is
above 70 F, the maximum stage will always be on when the
compressors are on.
On the initial start-up of a circuit, the condenser fans will
start 5 seconds prior to the compressor starting in order to ensure proper head pressure of the compressor immediately at
start-up. After the compressor starts, the normal head pressure
routine will begin 30 seconds after the condenser fan pre-start.
What stage fans starts depends on the outdoor ambient temperature. The three situations are:
OAT <
50 F
50 F < OAT < 70 F
OAT >
70 F
See Fig. 10-13 for what stage of fans starts for each
scenario.
ECONOMIZER INTEGRATION WITH MECHANICAL
COOLING — When the economizer is able to provide free
cooling (Run Status
cooling may be delayed or even held off indefinitely.
NOTE: Once mechanical cooling has started, this delay logic
is no longer relevant.
Multi-Stage Cooling Economizer Mechanical Cooling
Delay — This type of mechanical cooling delay is relevant to
the following machine control types:
If the economizer is able to provide free cooling at the start
of a cooling session, the mechanical cooling algorithm
(SumZ), checks the economizer’s current position (Run Status
ECONECn.P) and compares it to the economizer’s
maximum position (ConfigurationECONEC.MX) – 5%.
Once the economizer has opened beyond this point a 150 second timer starts. If the economizer stays beyond this point for
2.5 minutes continuously, the mechanical cooling algorithm is
allowed to start computing demand and stage compressors and
unloaders.
ECONACTV = YES), mechanical
Heating Control — The N Series ComfortLink controls
offers control for six different types of heating systems to satisfy
general space heating requirements: 2-stage gas heat, 2-stage
electric heat, SCR (modulating) electric heat, steam heat, modulating gas heat, and hydronic heat. Heating control also provides
tempering and reheat functions. These functions are discussed in
separate sections. Reheat is discussed under Dehumidification
function on page 87.
Variable air volume (VAV) type applications (C.TYP = 1 or
2) require that the space terminal positions be commanded to
open to minimum heating positions when gas or electric heat
systems are active, to provide for the unit heating system’s
Minimum Heating Airflow rate.
Also, for VAV applications, the heat interlock relay (HIR)
function provides the switching of a control signal intended for
use by the VAV terminals. This signal must be used to
command the terminals to open to their Heating Open positions. The HIR is energized whenever the Heating mode is active, an IAQ pre-occupied force is active, or if fire smoke
modes, pressurization, or smoke purge modes are active.
Hydronic and steam heating applications that use the unit’s
control require the installation of a communicating actuator on
the hydronic heating coil’s control valve. This actuator (with or
without matching control valve) may be separately shipped for
field installation.
All heating systems are available as factory-installed
options. The hydronic or steam heating coil may also be fieldsupplied and field-installed; the actuator is still required if unit
control will be used to manage this heating sequence.
POST FILTER APPLICATION — Gas heat controls also use
an airflow switch when post filter option is installed in unit.
Lack of airflow will prevent gas heat from operating.
Electric heat controls add filter temperature switches at the
post filters. The filter temperature switches will prevent electric
heat from operating when high temperatures are experienced.
SETTING UP THE SYSTEM — The essential heating configurations located at the local display under ConfigurationHEAT. See Table 34.
Heating Control Type (
available are selected/configured with this variable.
0 = No Heat
1 = 2 Stage Electric Heat
2 = 2 Stage Gas Heat
3 = Staged Gas Heat or Modulating Gas Heat
4 = Hydronic Heat (Hot Water or Steam)
5 = SCR Electric Heat
Heating Supply Air Set Point (
for either modulating gas, SCR electric, or hydronic heat, this
is the supply air set point for heating.
Occupied Heating Enable (
only applies when the unit’s control type (Configuration
UNITC.TYP) is configured for 1 (VAV-RAT) or 2 (VAV-
SPT). If the user wants to have the capability of performing
heating throughout the entire occupied period, then this
configuration needs to be set to “YES.” Most installations do
not require this capability, and if heating is installed, it is used
to heat the building up in the morning. In this case set OC.EN
to “NO.”
NOTE: This unit des not support simultaneous heating and
cooling. If significant simultaneous heating and cooling
demand is expected, it may be necessary to provide additional
heating or cooling equipment and a control system to provide
occupants with proper comfort.
MBB Sensor Heat Relocate (
the user additional performance benefit when under CCN
Linkage for the 2-stage electric and gas heating types. As twostage heating types do not “modulate” to a supply air set point,
no leaving air thermistor is required and none is provided. The
evaporator discharge thermistor, which is initially installed upstream of the heater, can be repositioned downstream and the
control can expect to sense this heat. While the control does not
need this to energize stages of heat, the control can wait for a
sufficient temperature rise before announcing a heating mode
to a CCN Linkage system (ComfortID™).
If the sensor is relocated, the user will now have the
capability to view the leaving-air temperature at all times at
Te mp e ra t ur e s
HT.CF) — The heating control types
HT.SP) — In a low heat mode
OC.EN) — This configuration
LAT.M) — This option allows
AIR.TCTRLLAT.
61
Table 34 — Heating Configuration
ITEMEXPANSIONRANGEUNITSCCN POINTDEFAULT
HEATHEATING CONFIGURATION
HT.CFHeating Control Type0 - 5HEATTYPE0*
HT.SPHeating Supply Air Setpt80 - 120dFSASPHEAT85
OC.ENOccupied Heating EnabledYes/NoHTOCCENANo
LAT.MMBB Sensor Heat RelocateYes/NoHTLATMONNo
NOTE: If the user does not relocate this sensor for the 2-stage
electric or gas heating types and is under CCN Linkage, then
the control will send a heating mode (if present)
unconditionally to the linkage coordinator in the CCN zoning
system regardless of the leaving-air temperature.
HEAT MODE SELECTION PROCESS — There are two
possible heat modes that the control will call out for heating
control: HVAC Mode = LOW HEAT and HVAC Mode =
HIGH HEAT. These modes will be called out based on control
type (C.TYP).
VAV- R AT (
C.TYP= 1) and VAV-SPT (C.TYP = 2) — There
is no difference in the selection of a heating mode for either
VAV-RAT or VAV-SPT, except that for VAV-SPT, space temperature is used in the unoccupied period to turn on the supply
fan for 10 minutes before checking return-air temperature. The
actual selection of a heat mode, LOW or HIGH for both control types, will be based upon the controlling return-air
temperature.
With sufficient heating demand, there are still conditions
that will prevent the unit from selecting a heat mode. First, the
unit must be configured for a heat type (Configuration
HEATHT.CF not equal to “NONE”). Second, the unit has a
configuration which can enable or disable heating in the
occupied period except for a standard morning warmup cycle
(Configuration
HEATOC.EN). See descriptions above in
the Setting Up the System section for more information.
Tstat-Multi-Stage (
C.TYP= 3) — With thermostat control
the W1 and W2 inputs determine whether the HVAC Mode is
LOW or HIGH HEAT.
W1 = ON, W2 = OFF: HVAC MODE = LOW HEAT*
W2 = ON, W2 = ON: HVAC MODE = HIGH HEAT
*If the heating type is either 2-stage electric or 2-stage gas, the
unit may promote a low heat mode to a high heat mode.
NOTE: If W2 = ON and W1 is OFF, a “HIGH HEAT” HVAC
Mode will be called out but an alert (T422) will be generated.
See Alarms and Alerts section on page 115.
SPT Multi-Stage (
C.TYP= 4) — The unit is free to select a
heating mode based on space temperature (SPT).
If the unit is allowed to select a heat mode, then the next
step is an evaluation of demand versus set point. At this point,
the logic is the same as for control types VAV-RAT and
VAV-SPT, (C.TYP = 1,2) except for the actual temperature
compared against set point. See Temperature Driven Heat
Mode Evaluation section below.
TEMPERATURE DRIVEN HEAT MODE EVALUATION —
This section discusses the technique for selecting a heating
mode based on temperature. Regardless of whether the unit is
configured for return air or space temperature the logic is exactly the same. For the rest of this discussion, the temperature
in question will be referred to as the controlling temperature.
First, the occupied and unoccupied heating set points under
Setpoints must be configured.
ITEMEXPANSION RANGE UNITS
OHSP
UHSP
Occupied Heat
Setpoint
Unoccupied
Heat Setpoint
55-80dFOHSP68
40-80dFUHSP55
CCN
POINT
DEFAULT
Then, the heat/cool set point offsets under Configura-
tion
BP
Related operating modes are under Operating Modes
D.LV.T should be set. See Table 35.
MODE.
ITEMEXPANSIONRANGECCN POINT
MODEMODES CONTROLLING UNIT
OCCCurrently OccupiedON/OFFMODEOCCP
T.C.STTemp.Compensated Start ON/OFFMODETCST
The first thing the control determines is whether the unit
is in the occupied mode (OCC) or in the temperature compensated start mode (T. C. S T). If the unit is occupied or in temperature compensated start mode, the occupied heating set point
(OHSP) is used. In all other cases, the unoccupied heating
setpoint (UHSP) is used.
The control will call out a low or high heat mode by
comparing the controlling temperature to the heating set point
and the heating set point offset. The set point offsets are used as
additional help in customizing and tweaking comfort into the
building space. See Fig. 14 for an example of offsets.
62
HEATING SET POINT
Fig. 14 — Heating Offsets
a48-8407
L.H.ON
L.H.OF
67.5 F
L.H.OF/2
H.H.ON
66.0 F
Demand Level Low Heat on Offset (
66.5 F
L.H.ON) — This is the
68.0 F
heating set point offset below the heating set point at which
point Low Heat starts.
Demand Level High Heat on Offset (
H.H.ON) — This is the
heating set point offset below [the heating set point minus
L.H.ON] at which point high heat starts.
Demand Level Low Heat Off Offset (
L.H.OF) — This is the
heating set point offset above [the heating set point minus
L.H.ON] at which point the Low Heat mode ends.
To enter into a LOW HEAT mode, if the controlling temperature falls below [the heating set point minus L.H.ON], then
HVAC mode = LOW HEAT.
To enter into a HIGH HEAT mode, if the controlling temperature falls below [the heating set point minus L.H.ON minus H.H.ON], then HVAC mode = HIGH HEAT.
To get out of a LOW HEAT mode, the controlling temperature must rise above [the heating set point minus L.H.ON plus
L.H.OF].
To get out of a HIGH HEAT mode, the controlling temperature must rise above [the heating set point minus L.H.ON plus
L.H.OF/2].
The Run Status table in the local display allows the user to
see the exact trip points for both the heating and cooling modes
without doing the calculations.
Heat Trend Demand Level (
H.T.LV) — This is the change in
demand that must be seen within the time period specified by
H.T.TM in order to hold off a HIGH HEAT mode regardless of
demand. This is not applicable to VAV control types (C.TYP=1
and 2) in the occupied period. This technique has been referred
to as “Comfort Trending.” As long as a LOW HEAT mode is
making progress in warming the space, the control will hold off
on a HIGH HEAT mode. This is relevant for the space sensor
machine control types (C.TYP = 4) because the unit may tran-
sition into the occupied mode and see an immediate and large
heating demand when the set points change.
Heat Trend Time (
H.T.TM) — This is the time period upon
which the heat trend demand level (H.T.LV) operates and may
work to hold off staging or a HIGH HEAT mode. This is not
applicable to VAV control types (C.TYP=1 and 2) in the
occupied period. See “Heat Trend Demand Level” section for
more details.
Table 35 — Heat/Cool Set Point Offsets
HEAT MODE DIAGNOSTIC HELP — To quickly determine the current trip points for the low and high heat modes,
there is a menu in the local display which lets the user quickly
view the state of the system. This menu also contains the cool
trip points as well. See Table 31 at the local display under Run
Status
TRIP.
The controlling temperature is “TEMP” and is in the middle
of the table for easy reference. Also, the “HVAC” mode can be
viewed at the bottom of the table.
TWO-STAGE GAS AND ELECTRIC HEAT CONTROL
(HT.CF = 1,2) — If the HVAC mode is LOW HEAT:
• If electric heat is configured, then the control will request
the supply fan ON
• If gas heat is configured, then the IGC and IFO (IGC fan
output) controls the supply fan request
• The control will turn on Heat Relay 1 (HS1)
• If evaporator discharge temperature is less than 50 F,
then the control will turn on Heat Relay 2 (HS2)*
*The logic for this “low heat” override is that one stage of
heating will not be able to raise the temperature of the supply
airstream sufficient to heat the space.
If the HVAC mode is HIGH HEAT:
• If electric heat is configured, then the control will request
the supply fan ON
• If gas heat is configured, then the IGC and IFO output
controls the supply fan request
• The control will turn on Heat Relay 1 (HS1)
• The control will turn on Heat Relay 2 (HS2)
HYDRONIC HEATING CONTROL (HT.CF = 4) — Hy-
dronic heating in N Series units refers to a hot water or steam
coil controlled by an actuator. This actuator is a communicating
actuator and may be field supplied. When Configuration
HEATHT.CF=4, there is a thermistor array called Te m -
peratures
AIR.TCCT, that is connected to the RXB, that
serves as the evaporator discharge temperature (EDT). The
leaving-air temperature (LAT) is assigned the thermistor that is
normally assigned to EDT and is located at the supply fan
housing (Te mp e ra t ur e s
AIR.TSAT).
The configurations for hydronic heating are located at
the local displays under Configuration
HEATHH.CF.
See Table 36.
Hydronic Heating Control Proportional Gain (
HW.P) — This
configuration is the proportional term for the PID which runs in
the HVAC mode LOW HEAT.
Hydronic Heating Control Integral Gain (
HW.I) — This
configuration is the integral term for the PID which runs in the
HVAC mode LOW HEAT.
Hydronic Heating Control Derivative Gain (
HW.D) — This
configuration is the derivative term for the PID which runs in
the HVAC mode LOW HEAT.
Hydronic Heating Control Run Time Rate (
HW.TM) —
This configuration is the PID run time rate which runs in the
HVAC mode LOW HEAT.
ITEMEXPANSIONRANGEUNITSCCN POINTDEFAULT
D.LV.TCOOL/HEAT SETPT. OFFSETS
L.H.ONDmd Level Lo Heat On-1 - 2^FDMDLHON1.5
H.H.ONDmd Level(+) Hi Heat On0.5 - 2.0^FDMDHHON0.5
L.H.OFDmd Level(-) Lo Heat Off0.5 - 2^FDMDLHOFF1
L.C.ONDmd Level Lo Cool On-1 - 2^FDMDLCON1.5
• The control will modulate the hot water or steam coil
actuator to the heating control point (Run Sta-
tus
VIEWHT.C.P). The heating control point for
hydronic heat is the heating supply air set point (Set-
points
SA.HT).
If the HVAC mode is HIGH HEAT:
• The control will command the supply fan on
• The control will command the hot water coil actuator to
100%.
Hydronic Heating PID Process
LOW HEAT, then the hydronic heating actuator will modulate
to the heating control point (Run Status
Control is performed with a generic PID loop where:
Error = Heating Control Point (HT.C.P) – Leaving Air Tem-
perature (LAT)
The PID terms are calculated as follows:
P = K * HW.P * error
I = K * HW.I * error + “I” last time through
D = K * HW.D * (error – error last time through)
Where K = HW.TM/60 to normalize the effect of changing the
run time rate.
NOTE: The PID values should be not be modified without
approval from Carrier.
Freeze Status Switch Logic (
the freezestat input (FRZ) alarms, indicating that the coil is
freezing, normal heat control is overridden and the following
actions will be taken:
1. Command the hot water coil actuator to 100%.
2. Command the economizer damper to 0%.
3. Command the supply fan on.
Configuring Hydronic Heat to Communicate Via Actuator
Serial Number — Every actuator used in the N Series control
system has its own unique serial number. The rooftop control
uses this serial number to communicate with the actuator.
These serial numbers are programmed at the factory and
should not need changing. Should field replacement of an actuator become necessary, it will be required to configure the serial numbers of the new actuator. Four individual numbers make
up this serial number and these can be programmed to match
the serial number of the actuator in its Hydronic Heating Actuator Configs group, ACT.C (SN.1, SN.2, SN.3, SN.4). See
Fig. 15.
NOTE: The serial numbers for all actuators can be found
inside the control doors of the unit as well as on the actuator
itself. If an actuator is replaced in the field, it is a good idea to
— If the HVAC mode is
VIEWHT.C.P).
InputsGEN.IFRZ.S) — If
Table 36 — Hydronic Heat Configuration
remove the additional peel off serial number sticker on the
actuator and cover up the old one inside the control doors.
MODULATING GAS HEAT CONTROL (HT.CF = 3 andHT.ST = 0, 1, 2, or 3) — As an option, the units with gas heat
can be equipped with modulating gas heat controls that will
provide infinite stages of heat capacity. This is intended for
tempering mode and tempering economizer air when in a cooling mode and the dampers are at minimum vent position. Tempering can also be used during a pre-occupancy purge to prevent low temperature air from being delivered to the space.
Tempering for staged gas, modulating gas, and hydronic heat
will be discussed in its own section. This section will focus on
heat mode control, which ultimately is relevant to tempering,
minus the consideration of the supply air heating control point.
The modulating gas and SCR electric heat configurations
are located at the local display under Configura-
tion
HEATSG.CF. See Table 37.
SCR ELECTRIC HEAT CONTROL (HT.CF = 5, no req.
set HT.ST) — As an option, the units with electric heat can be
equipped with modulating SCR electric heater controls that
will provide infinite stages of heat capacity. This is intended for
tempering mode and tempering economizer air when in a cooling mode and the dampers are at minimum vent position. Tempering can also be used during a pre-occupancy purge to prevent low temperature air from being delivered to the space.
Tempering for modulating gas, hydronic and SCR electric heat
will be discussed in its own section. This section will focus on
heat mode control, which ultimately is relevant to tempering,
minus the consideration of the supply air heating control point.
Staged Heat Type (
control as to how many stages and in what order they are
staged. Setting HT.ST = 0, 1, 2, or 3 configures the unit for
Modulating Gas Heat.
Max Cap Change per Cycle (
tion limits the maximum change in capacity per PID run time
cycle.
St.Ht DB Min.dF/PID Rate (M.R.DB) — This configuration
is a deadband minimum temperature per second rate. See
capacity calculation logic on this page for more details.
St.Heat Temp.Dead Band (
S.G.DB) — This configuration is
a deadband delta temperature. See capacity calculation logic on
this page for more details.
Heat Rise in dF/Sec Clamp (
RISE) — This configuration
clamps heat staging up when the leaving-air temperature is
rising too fast.
LAT Limit Config (
LAT.L) — This configuration senses
when leaving air temperature is outside a delta temperature
band around set point and allows staging to react quicker.
Limit Switch Monitoring? (
LIM.M) — This configuration
allows the operation of the limit switch monitoring routine.
This is always enabled for 48N Series as a limit switch temperature sensor is always present for modulating gas operation. It
is not used on SCR electric heat units.
Limit Switch High Temp (
SW.H.T) — This configuration is
the temperature limit above which stages of heat will be shed.
Limit Switch Low Temp (
SW.L.T) — This configuration is
the temperature limit above which no additional stages of heat
will be allowed.
Heat Control Prop. Gain (
HT.P) — This configuration is the
proportional term for the PID which runs in the HVAC mode
LOW HEAT.
Heat Control Derv. Gain (
HT.D) — This configuration is the
derivative term for the PID which runs in the HVAC mode
LOW HEAT.
Heat PID Rate Config (
HT.TM) — This configuration is the
PID run time rate.
Staged Heating Logic
— If the HVAC mode is HIGH HEAT:
• On 48N units, the supply fan for staged heating is con-
trolled by the integrated gas control (IGC) boards and
unless the supply fan is on for a different reason, will be
controlled by the IFO. On 50N units, the fan is ON
whenever the heat is ON.
• Command all stages of heat ON
If the HVAC mode is LOW HEAT:
• On 48N units, the supply fan for modulating gas heating
is controlled by the integrated gas control (IGC) boards
and unless the supply fan is on for a different reason, will
be controlled by the IGC IFO input. On 50N units, the
fan is ON whenever the heat is ON.
• The unit will control stages of heat to the heating control
point (Run Status
VIEWHT.C.P). The heating con-
trol point in a LOW HEAT HVAC mode for staged heat
is the heating supply air set point (Setpoints
Staged Heating PID Logic
— The heat control loop is a PID
SA.HT).
design with exceptions, overrides and clamps. Capacity rises
and falls based on set point and supply-air temperature. When
the ComfortLink control is in Low Heat or Tempering Mode
(HVAC mode), the algorithm calculates the desired heat capacity. The basic factors that govern the controlling technique are:
• how frequently the algorithm is run.
• the amount of proportional and derivative gain applied.
• the maximum allowed capacity change each time this
algorithm is run.
• deadband hold-off range when rate is low.
This routine is run once every “HT.TM” seconds. Every
time the routine is run, the calculated sum is added to the control output value. In this manner, integral effect is achieved.
Every time this algorithm is run, the following calculation is
performed:
Error = HT.C.P – LAT
Error_last = error calculated previous time
P = HT.P*(Error)
D = HT.D*(Error – Error_last)
The P and D terms are overridden to zero if:
Error < S.G.DB AND Error > – S.G.DB AND D < M.R.DB
AND D > – M.R.DB.
“P + D” are then clamped based on CAP.M. This sum can be
no larger or no smaller than +CAP.M or –CAP.M.
Finally, the desired capacity is calculated:
Staged Heat Capacity Calculation = “P + D” + old Staged Heat
Capacity Calculation.
NOTE: The PID values should not be modified without
approval from Carrier.
IMPORTANT: When gas or electric heat is used in a VAV
application with third party terminals, the HIR relay output
must be connected to the VAV terminals in the system in
order to enforce a minimum heating cfm. The installer is
responsible to ensure the total minimum heating cfm is not
below limits set for the equipment. Failure to do so will
result in limit switch tripping and may void warranty.
Modulating Gas Heat Staging
— Different unit sizes will
control heat stages differently based on the amount of heating
capacity included. These staging patterns are selected based on
the unit model number. The selection of a set of staging patterns is controlled via the heat stage type configuration parameter Configuration→HEAT→SG.CF→HT.ST. Setting HT.ST
to 0, 1, 2, or 3 configures the unit for Modulating Gas Heat.
The selection of HT.ST = 0, 1, 2, or 3 is based on the unit size
and heat size. See Table 38.
As the heating capacity rises and falls based on demand, the
modulating gas control logic will stage the heat relay patterns
up and down respectively (Run Status→VIEW→HT.ST) and
set the capacity of the Modulating Gas section (Outputs→HEAT→H1.CP). The Heat Stage Type configuration selects
one of the staging patterns that the modulating gas control will
use. In addition to the staging patterns, the capacity for each
stage is also determined by the modulating gas heating PID algorithm. Therefore, choosing the heat relay outputs and setting
65
the modulating gas section capacity is a function of the capacity desired, the available heat staging patterns configured with
heat stage type (HT.ST), and the capacity range presented by
each staging pattern.
As the modulating gas control desired capacity rises, it is
continually checked against the capacity ranges of the next
higher staging patterns. Since each stage has a range of capacities, and the capacities of some stages overlap, the control selects the highest stage with sufficient minimum capacity.
Similarly, as the modulating gas control desired capacity
drops, it is continually checked against the capacity ranges of
the next lower stages. The control selects the lowest stage with
sufficient maximum capacity.
The first two modulating gas heat outputs are located on the
MBB. Outputs 3, 4, 5, 6, and the analog output that sets the
modulating gas section capacity are located on the SCB outputs 7 and 8 are located on the CXB. The heat stage selected
(Run Status→VIEW→HT.ST) is clamped between 0 and the
Table 39 — Modulating Gas Heat Control Steps (HT.ST = 0)
maximum number of stages possible (Run Status→VIEW→H.MAX). See Tables 39- 42.
SCR Electric Heat Staging
— For all SCR electric heat units
there is only 1 heat stage. Whenever the heat is energized, all
heaters will be active will be modulatied through The SCR
control.
Table 38 — Modulating Gas Heat
NUMBER
OF
STAGES
30275, 90, 105Low
413
524
735120,130,150High
HT.ST
CONFIG.
No. of
Heat
Exchanger
Sections
UNIT SIZE
48N
75High
90, 105Med
120,130,150Low
90-105High
120,130,150Med
HEAT
SIZE
RELAY OUTPUT
STAGE
0OFFOFFOFFOFF00
1ONOFF/ON*OFFOFF1550
2ONOFF/ON*ONOFF5288
3ONOFF/ON*ONON65100
* ON when OutputsHEATH1.CP > 54%, OFF when OutputsHEATH1.CP < 46%.
Heat 1Heat 2Heat 3Heat 4
MBB-RLY8TR1-CRSCB-RLY1SCB-RLY2
IGC1MGV1IGC2MGV2MINMAX
CAPACITY
%
Table 40 — Modulating Gas Heat Control Steps (HT.ST = 1)
RELAY OUTPUT
STAGE
0OFFOFFOFFOFFOFFOFF00
1ONOFF/ON*OFFOFFOFFOFF1033
2ONOFF/ON*ONOFFOFFOFF3558
3ONOFF/ON*ONOFFONOFF6083
4ONOFF/ON*ONONONON76100
* ON when OutputsHEATH1.CP > 54%, OFF when OutputsHEATH1.CP < 46%.
Heat 1Heat 2Heat 3Heat 4Heat 5Heat 6
MBB-RLY8TR1-CRSCB-RLY1SCB-RLY2SCB-RLY3SCB-RLY4
IGC1MGV1IGC2MGV2IGC3MGV3MINMAX
CAPACITY
%
Table 41 — Modulating Gas Heat Control Steps (HT.ST = 2)
STAGE
0OFFOFFOFFOFFOFFOFFOFFOFF00
1ONOFF/ON*OFFOFFOFFOFFOFFOFF725
2ONOFF/ON*ONOFFOFFOFFOFFOFF2644
3ONOFF/ON*ONOFFONOFFOFFOFF4563
4ONOFF/ON*ONOFFONOFFONOFF6481
5ONOFF/ON*ONONONONONON82100
* ON when OutputsHEATH1.CP > 54%, OFF when OutputsHEATH1.CP < 46%.
Table 42 — Modulating Gas Heat Control Steps (HT.ST = 3)
RELAY OUTPUT
STAGE
* ON when OutputsHEATH1.CP > 54%, OFF when OutputsHEATH1.CP < 46%.
log output that sets the SCR electric heat section capacity is located on the SCB.
Limit Switch Temperature Monitoring (
air volume applications in the low heat or tempering mode can
experience low airflow and as a result it is possible for nuisance
trips of the gas heat limit switch, thereby shutting off all gas
stages. In order to achieve consistent heating in a tempering
mode, a thermistor (Te mp e ra t ur e s
next to the limit switch and monitored for overheating. In order
to control a tempering application where the limit switch
temperature has risen above either the upper or lower configuration parameters (SW.L.T, SW.H.T), the staged gas control
will respond by clamping or droping gas stages. See Table 43.
(LIM.M) is set to YES, all the modes will be monitored. If set
to NO, then only LAT Cutoff mode and Capacity Clamp mode
for RISE will be monitored.
through the capacity calculation) is greater than (RISE)
degrees F per second, the control will not allow the capacity
routine to add stages and will turn on the Capacity Clamp
mode.
ity routine immediately and drop all heat stages and will turn
on the Limiting mode.
Capacity Clamp mode and Limiting mode with one exception.
If (LAT – LAT last time through the capacity calculation) is
greater than “RISE” degrees F per second, the control will stay
in the Capacity Clamp mode.
below SW.L.T, and LAT is not rising quickly, the control will
run the capacity calculation routine immediately and allow a
full stage to come back on if desired this first time through
upon recovery. This will effectively override the “max capacity
stage” clamp.
for the supply-air temperature to rise and fall radically between
capacity calculations, thereby impacting the limit switch temperature. In the case where supply-air temperature (LAT) rises
above the control point (HT.C.P) + the cutoff point (LAT.L) the
The electric heat outputs are located on the MBB. The ana-
and drop a stage of heat. Thereafter, every time the capacity
calculation routine runs, provided the control is still in the LAT
cutoff mode condition, a stage will drop each time through.
LIM.M) — Variable
Falling back below the cutoff point will turn off the LAT cutoff
mode.
CONTROL BOARD INFORMATION
AIR.TS.G.LS) is placed
Integrated Gas Control (IGC)
each bank of gas heat exchangers; 2, 3, 4, or 5 IGC are used depending on unit size and heat capacity. The IGC controls the
— One IGC is provided with
direct spark ignition system and monitors the rollout switch,
limit switches, and induced-draft motor Hall Effect switch. For
units equipped with Modulating Gas heat, the IGC in the Modulating Gas section uses a Pressure Switch in place of the Hall
Effect sensor. The IGC is equipped with a LED (light-emitting
Table 43 — SCR Electric Heat Control Steps
STAGE
0OFFOFF0 0
1ONON0100
RELAY OUTPUTCAPACITY (%)
Heat1Heat2Min.Max.
If the Limit Switch Monitoring configuration parameter
diode) for diagnostics. See Table 44.
Integrated Gas Control Board Logic
— This board provides
control for the ignition system for the gas heat sections.
When a call for gas heat is initiated, power is sent to W on
the IGC boards. For standard 2-stage heat, all boards are wired
in parallel. For modulating gas heat, each board is controlled
separately. When energized, an LED on the IGC board will be
turned on. See Table 44 for LED explanations.
Each board will ensure that the rollout switch and limit
switch are closed. The induced-draft motor is then energized.
If S.G.LS rises above SW.L.T or if (LAT – LAT last time
For units equipped with 2-stage gas heat the speed of the motor
is proven with a Hall Effect sensor on the motor. For units
equipped with modulating gas heat the motor function is proven with a pressure switch. When the motor speed or function is
proven, the ignition activation period begins. The burners ig-
If S.G.LS rises above SW.H.T the control will run the capac-
nite within 5 seconds. If the burners do not light, there is a 22second delay before another 5-second attempt is made. If the
burners still do not light, this sequence is repeated for 15 minutes. After 15 minutes have elapsed and the burners have not
If S.G.LS falls below SW.L.T the control will turn off both
ignited then heating is locked out. The control will reset when
the request for W (heat) is temporarily removed.
When ignition occurs, the IGC board will continue to monitor the condition of the rollout switch, limit switches, Hall Effect sensor or pressure switch, and the flame sensor. Forty-five
If control is in the Limiting mode and then S.G.LS falls
seconds after ignition has occurred, the IGC will request that
the indoor fan be turned on.
The IGC fan output (IFO) is connected to the indoor fan input on the MBB which will indicate to the controls that the indoor fan should be turned on (if not already on). If for some
reason the overtemperature limit switch trips prior to the start
In addition to the above checks, it is also possible at low cfm
of the indoor fan blower, on the next attempt the 45-second delay will be shortened by 5 seconds. Gas will not be interrupted
to the burners and heating will continue. Once modified, the
fan delay will not change back to 45 seconds unless power is
reset to the control.
CAPACITY
control will run the capacity calculation routine immediately
%
67
The IGC boards only control the first stage of gas heat on
each gas valve. The second stages are controlled directly from
the MBB board for staged gas. For units equipped with modulating gas heat, the second stage is controlled from the timer relay board (TR1). The IGC board has a minimum on-time of 1
minute.
In modes such as Service Test where long minimum on
times are not enforced, the 1-minute timer on the IGC will still
be followed and the gas will remain on for a minimum of 1
minute.
Staged Gas Heat Board (SCB)
— When optional modulating
gas heat is used, the SCB board is installed and controls additional stages of gas heat. The SCB also provides additional sensors for monitoring of the supply-air and limit switch temperatures. For units equipped with modulating gas heat, the SCB
provides the 4 to 20 mA signal to the SC30 board that sets the
modulating gas section capacity. This board is located in the
main unit control box.
Timer Relay Control Board (TR1)
— The TR1 is used on
modulating gas heat equipped units only. It is located in the gas
heat section and is used in combination with the SC30 to provide control of the modulating gas heat section. The TR1 receives an input from the IGC, initiates a start-up sequence,
powers the SC30, sets the induced-draft motor speed, and provides the main gas valve high fire input. When the start-up sequence is complete, the TR1 checks the input from the SC30 to
determine which state to command the induced-draft motor
and main gas valve. See Table 45.
Signal Conditioner Control Board (SC30)
— The SC30 is
used on modulating gas heat equipped units only. It is located
in the gas heat section and is used in combination with the TR1
to provide control of the modulating gas heat section. The
SC30 is powered by an output from the TR1. It receives a
capacity input from the SCB, provides a capacity output to the
modulating gas valve, and provides an output to the TR1 to
determine which state to command the induced-draft motor
and main gas valve. See Table 45.
Modulating Gas Control Boards (SC30 and TR1) Logic
—
All gas modulating units are equipped with one timer relay
board (TR1) and one signal conditioner board (SC30), regardless the unit size. The boards provide control for variable heating output for the gas heat section.
Similar with staged gas heat option, each IGC board is controlled separately. The IGC functions are not affected by the
modulating gas control logic. When a call for gas heat is initiated, W on the IGC board and the timer relay board (TR1) are
energized. The LED on TR1 board will be turned on. See
Table 45 for LED explanation.
When TR1 received an input from the IGC board, the relay
board starts Timer no. 1 or start-up sequence: sets the gas valve
stage and the inducer motor speed, and enables the signal conditioner board SC30. During Timer no. 1, the SC30 board
keeps a fixed heating output. When Timer no. 1 expires, the
modulating gas control boards start Timer no. 2. Throughout
the duration of Timer no. 2, the boards determine which state to
adjust the capacity output to satisfy the heat demand. When
Timer no. 2 expires, the boards receive a capacity input from
the SCB board and continuous modulate the heat output until
the mode selection sensor is satisfied.
Table 44 — IGC LED Indicators
ERROR CODELED INDICATION
Normal OperationOn
Hardware FailureOff
Fan On/Off Delay Modified1 Flash
Limit Switch Fault2 Flashes
Fame Sense Fault3 Flashes
Five Consecutive Limit Switch Faults4 Flashes
Ignition Lockout Fault5 Flashes
Ignition Switch Fault6 Flashes
Rollout Switch Fault7 Flashes
Internal Control Fault8 Flashes
Software Lockout9 Flashes
NOTES:
1. There is a 3-second pause between error code displays.
2. If more than one error code exists, all applicable error codes will
be displayed in numerical sequence.
3. Error codes on the IGC will be lost if power to the unit is
interrupted.
Table 45 — TR1 Board LED Indicators
LED
DESIGNATION
ON24 VAC Supplied to TR1
SRInput received from IGC2, starts timer no. 1
MR
FRIDM2 operates at high speed
CR
Modulating Gas Valve modulated except during
fixed output delay time
Modulating Gas Valve operates in high pressure
stage
RESULT/ACTION
The IGC boards only control the first stage of gas heat on
each gas valve. The second stages are controlled directly from
the MBB board. The IGC board has a minimum on-time of 1
minute.
In modes such as Service Test where long minimum on
times are not enforced, the 1-minute timer on the IGC will still
be followed and the gas will remain on for a minimum of 1
minute.
RELOCATE SAT FOR HEATING-LINKAGE APPLICATIONS — If Configuration
the supply air temperature thermistor (Temperatures
SAT) must be relocated downstream of the installed heating
HEATLAT.M is set to YES,
AIR.T
device. This only applies to two-stage gas or electric heating
types (Configuration
HEAT HT.CF=1 or 2).
Determine a location in the supply duct that will provide a
fairly uniform airflow. Typically this would be a minimum of
5 equivalent duct diameters downstream of the unit. Also, care
should be taken to avoid placing the thermistor within a direct
line-of-sight of the heating element to avoid radiant effects.
Run a new two-wire conductor cable from the control box
through the low voltage conduit into the space inside the building and route the cable to the new sensor location.
Installing a New Sensor
— Procure a duct-mount temperature
sensor (Carrier P/N 33ZCSENPAT or equivalent 10,000 ohm
at 25C NTC [negative temperature coefficient] sensor). Install
the sensor through the side wall of the duct and secure.
Re-Using the Factory SAT Sensor
— The factory sensor is
attached to the left-hand side of the supply fan housing.
Disconnect the sensor from the factory harness. Fabricate a
mounting method to insert the sensor through the duct wall and
secure in place.
Attach the new conductor cable to the sensor leads and terminate in an appropriate junction box. Connect the opposite
end inside the unit control box at the factory leads from MBB
J8 terminals 11 and 12 (PNK) leads. Secure the unattached
PNK leads from the factory harness to ensure no accidental
contact with other terminals inside the control box.
68
TEMPERING MODE — In a vent or cooling mode, the
economizer at minimum position may send extremely cold
outside air down the ductwork of the building. Therefore it
may be necessary to bring heat on to counter-effect this low
supply-air temperature. This is referred to as the tempering
mode.
Setting up the System
— The relevant set points for temper-
ing are located at the local display under Setpoints:
ITEMEXPANSIONRANGE UNITS
T.P RG
T.C L
T.V. OC
T.V. UN
Operation
Tempering
Purge SASP
Tempering in
Cool Offset
Tempering Vent
Occ SASP
Tempering Vent
Unocc. SASP
— First, the unit must be in a vent mode, a low cool,
–20-80dFTEMPPURG50
5-75^FTEMPCOOL5
–20-80dFTEMPVOCC65
–20-80dFTEMPVUNC50
CCN
POINT
DEFAULT
or a high cool HVAC mode to be considered for a tempering
mode. Secondly, the tempering mode is only allowed when the
rooftop is configured for modulating gas, SCR electric heat, or
hydronic heating (Configuration
HEATHT.CF=3 or 4).
Also, if OAT is above the chosen tempering set point, temper-
ing will not be allowed. Additionally, tempering mode is
locked out if any stages of mechanical cooling are present.
If the control is configured for staged gas, modulating gas,
SCR electric heat, or hydronic heating and the control is in a
vent, low cool, or high cool HVAC mode, and the rooftop control is in a situation where the economizer must maintain a
minimum position/minimum cfm, then the evaporator discharge temperature (EDT) will be monitored. If the EDT falls
below a particular trip point then tempering mode may be
called out:
HVAC mode = “Tempering Vent”
HVAC mode = “Tempering LoCool”
HVAC mode = “Tempering HiCool”
The decision making/selection process for the tempering
trip set point is as follows:
If an HVAC cool mode is in effect, then the tempering cool
point is SASP – T.CL.
If not in effect and unit is in a pre-occupied purge mode
(Operating Modes
MODEIAQ.P=ON), then the trip point
is T. PR G.
If not in effect and unit is in an occupied mode (Operating
Modes
MODEIAQ.P=ON), then the trip point is
TEMPVOCC.
For all other cases, the trip point is TEMPVUNC.
NOTE: The unoccupied economizer free cooling does not
qualify as a HVAC cool mode as it is an energy saving feature
and has its own OAT lockout already. The unoccupied free
cooling mode (HVAC mode = Unocc. Free Cool) will override
any unoccupied vent mode from triggering a tempering mode.
A minimum amount of time must pass before calling out
any tempering mode. In effect, the EDT must fall below the
trip point value –1° F continuously for a minimum of 2 minutes. Also, at the end of a mechanical cooling cycle, a 10-minute delay will be enforced before considering a tempering during vent mode in order to allow any residual cooling to dissipate from the evaporator coil.
If the above conditions are met, the algorithm is free to
select the tempering mode (MODETEMP).
If a tempering mode becomes active, the modulating heat
source (staged gas, modulating gas, SCR electric heat, or hot
water) will attempt to maintain leaving-air temperature (LAT)
at the tempering set point used to trigger the tempering mode.
The technique for modulation of set point for staged gas, modulating gas, SCR electric heat, and hydronic heat is the same as
in a heat mode. More information regarding the operation of
heating can be referenced in the Heating Control section.
Recovery from a tempering mode (MODETEMP) will
occur when the EDT rises above the trip point. On any change
in HVACMODE, the tempering routine will re-assess the tempering set point which may cause the control to continue or exit
tempering mode.
Static Pressure Control — Variable air volume (VAV)
air-conditioning systems must provide varying amounts of air
to the conditioned space. As air terminals downstream of the
unit modulate their flows, the unit must simply maintain control over duct static pressure in order to accommodate the
needs of the terminals, and therefore to meet the varying combined airflow requirement. The unit design includes an optional means of accommodating this requirement. This section describes the technique by which this control takes place.
A unit intended for use in a VAV system can be equipped
with a variable frequency drive (VFD) for the supply fan. The
speed of the fan can be controlled directly by the ComfortLink
controls. A duct static pressure transducer is located in the auxiliary control box. The signal from the pressure sensor is received by the RCB board and is then used in a PID control routine that outputs a fan speed to the VFD.
The PID routine periodically calculates the static pressure
error from set point. This error at any point in time is simply
the duct static pressure set point minus the measured duct static. It is the Proportional term of the PID. The routine also calculates the Integral of the error over time, and the Derivative
(rate of change) of the error. A calculated value is then used to
create an output signal used to adjust the VFD to maintain the
static pressure set point.
SETTING UP THE SYSTEM — Here are the options under the Local Display Mode Configuration
Static Pressure Configuration (
SP.CF) — This variable is
used to configure the use of ComfortLink for static pressure
control. It has the following options:
• 0 (DISABLED) - No static pressure control by Com-
fortLink controls. This would be used for a constant volume (CV) application when static pressure control is not
required or for a VAV application if there will be thirdparty control of the VFD. In this latter case, a suitable
means of control must be field installed.
• 1 (ENABLED) - This will enable the use of ComfortLink
controls
Staged Air Volume Control (
SP.SV) — This variable enabled
the use of a CV unit with VFD for staged air volume control.
Static Pressure Sensor (
SP.S) — This variable enables the use
of a supply duct static pressure sensor. This must be enabled to
use ComfortLink controls for static pressure control. If using a
third-party control for the VFD then this should be disabled.
Static Pressure Low Range (
SP.LO) — This is the minimum
static pressure that the sensor will measure. For most sensors
this will be 0 in. wg. ComfortLink controls will map this value
to a 4 mA sensor output.
Static Pressure High Range (
SP.HI) — This is the maximum
static pressure that the sensor will measure. Commonly this
will be 5 in. wg. The ComfortLink controls will map this value
to a 20 mA sensor output when the signal is 20 mA.
Static Pressure Set Point (
SP.SP) — This is the static pressure control point. It is the point against which ComfortLink
controls compares the actual measured supply duct pressure for
determination of the error that is used for PID control. Adjust
SP.SP to the minimum value necessary for proper operation of
air terminals in the conditioned space at full load and part load.
Too high a value will cause unnecessary fan motor power consumption at part load conditions and/or noise problems. Too
low a value will result in insufficient airflow.
SP. See Table 46.
69
VFD Minimum Speed (
speed for the supply fan VFD. Typically the value is chosen to
maintain a minimum level of ventilation.
NOTE Most VFDs have a built-in minimum speed adjustment
which should be configured fort 0% when using ComfortLink
controls for static pressure control..
VFD Maximum Speed (
speed for the supply fan VFD. This is usually set to 100%.
VFD Fire Speed Override (
the supply fan VFD will use during the fire modes; pressurization, evacuation and purge. This is usually set to 100%.
Static Pressure Reset Configuration (
is used to configure the static pressure reset function. When
SP.RS = 0, there is no static pressure reset via an analog input.
When SP.RS = 1, there is static pressure reset based on the
CEM 4-20 mA input and ranged from 0 to 3 in. wg. When
SP.RS = 2, there is static pressure reset based on RAT and defined by SP.RT and SP.LM. When SP.RS = 3, there is static
pressure reset based on SPT and defined by SP.RT and SP.LM.
When SP.RS = 4, there is VFD speed control where 0 mA =
0% speed and 20 mA = 100% (SP.MN and SP.MX will over-
ride).
Static Pressure Reset Ratio (
the reset ratio in terms of static pressure versus temperature.
The reset ratio determines how much the static pressure is reduced for every degree below set point for RAT or SPT.
Static Pressure Reset Limit (
the maximum amount of static pressure reset that is allowed.
This is sometimes called a "clamp."
NOTE: Resetting static pressure via RAT and SPT is primarily
a constant volume application which utilizes a VFD. The reasoning is that there is significant energy savings in slowing
down a supply fan as opposed to running full speed with supply air reset. Maintaining the supply air set point and slowing
down the fan has the additional benefit of working around
dehumidification concerns.
Static Pressure PID Config (
configuration can be accessed under this heading in the Con-
figuration
SP submenu. Under most operating conditions
SP.MN) — This is the minimum
SP.MX) — This is the maximum
SP.FS) — This is the speed that
SP.RS) — This option
SP.RT) — This option defines
SP.LM) — This option defines
S.PID) — Static pressure PID
the control PID factors will not require any adjustment and the
factory defaults should be used. If persistent static pressure
fluctuations are detected, small changes to these factors may
improve performance. Decreasing the factors generally reduce
the responsiveness of the control loop, while increasing the factors increase its responsiveness. Note the existing settings before making changes, and seek technical assistance from Carrier before making significant changes to these factors.
Static Pressure PID Run Rate (S.PID
SP.TM) — This is the
number of seconds between duct static pressure readings taken
by the ComfortLink PID routine.
Static Pressure Proportional Gain (S.PID
SP.P) — This is
the proportional gain for the static pressure control PID control
loop.
Static Pressure Integral Gain (S.PID
SP.I) — This is the
integral gain for the static pressure control PID control loop.
Static Pressure Derivative Gain (S.PID
SP.D) — This is the
derivative gain for the static pressure control PID control loop.
RELATED POINTS — These points represent static pressure
control and static pressure reset inputs and outputs. See Table 47.
Static Pressure mA (
SP.M) — This variable reflects the value
of the static pressure sensor signal received by ComfortLink
controls. It may in some cases be helpful in troubleshooting.
Static Pressure mA Trim (
SP.M.T) — This input allows a
modest amount of trim to the 4 to 20mA static pressure transducer signal, and can be used to calibrate a transducer.
Static Pressure Reset (
SP.RS) — This variable reflects the
value of the static pressure reset signal applied from a CCN
system.
Static Pressure Reset mA (
SP.R.M) —This input reflects the
value of the static pressure transducer reset signal applied from
a CCN system.
Static Pressure Reset Sensor (
SP.RS) — This variable can be
configured to allow static pressure reset from a CCN system.
See relevant CCN documentation for additional details.
Supply Fan VFD Speed (
S.VFD) — This output can be used
to check on the actual speed of the VFD. This may be helpful
in some cases for troubleshooting.
— The ComfortLink controls supports the use
of static pressure reset. For static pressure reset to occur, the
unit must be part of a CCN system with access to CCN reset
variable and the Linkage Master Terminal System Logic. The
Linkage Master terminal monitors the primary air damper position of all the terminals in the system (done through LINKAGE
with the new ComfortID™ air terminals).
It then calculates the amount of supply static pressure reduction necessary to cause the most open damper in the system to
open more than the minimum value (60%) but not more than
the maximum value (90% or negligible static pressure drop).
This is a dynamic calculation, which occurs every two minutes
whenever the system is operating. The calculation ensures that
the supply static pressure is always enough to supply the required airflow at the worst case terminal but never more than
necessary, so that the primary air dampers do not have to operate with an excessive pressure drop (more than required to
maintain the airflow set point of each individual terminal in the
system). As the system operates, if the most open damper
opens more than 90%, the system recalculates the pressure reduction variable and the value is reduced. Because the reset
value is subtracted from the controlling set point at the equipment, the pressure set point increases and the primary air
dampers close a little (to less than 90%). If the most open
damper closes to less than 60%, the system recalculates the
pressure reduction variable and the value is increased. This results in a decrease in the controlling set point at the equipment,
which causes the primary air dampers to open a little more (to
greater than 60%).
The rooftop unit has the design static pressure set point programmed into the CCN control. This is the maximum set point
that could ever be achieved under any condition. To simplify
the installation and commissioning process for the field, this
system control is designed so that the installer only needs to enter a maximum duct design pressure or maximum equipment
pressure, whichever is less. There is no longer a need to calculate the worst case pressure drop at design conditions and then
hope that some intermediate condition does not require a higher supply static pressure to meet the load conditions. For
example, a system design requirement may be 1.2 in. wg, the
equipment may be capable of providing 3.0 in. wg and the supply duct is designed for 5.0 in. wg. In this case, the installer
could enter 3.0 in. wg as the supply static pressure set point and
allow the air terminal system to dynamically adjust the supply
duct static pressure set point as required.
The system will determine the actual set point required delivering the required airflow at every terminal under the current
Table 47 — Static Pressure Reset Related Points
load conditions. It will always be the lowest value under the
given conditions, and as the conditions and airflow set point at
each terminal change throughout the operating period, and so
will the equipment static pressure set point.
The CCN system must have access to a CCN variable
(SPRESET which is part of the equipment controller). In the
algorithm for static pressure control, the SPRESET value is always subtracted from the configured static pressure set point
by the equipment controller. The SPRESET variable is always
checked to be a positive value or zero only (negative values are
clamped to zero). The result of the subtraction of the SPRESET
variable from the configured set point is limited so that it cannot be less than zero.
The result is that the system will dynamically determine the
required duct static pressure based on the actual load conditions currently in the space. It eliminates the need to calculate
the design supply static pressure set point (although some may
still want to do it anyway). It also saves the energy that is the
difference between the design static pressure set point and the
required static pressure (multiplied by the airflow). Normally,
the VAV system operates at the design static pressure set point
all the time, however, a typical VAV system operates at design
conditions less than 2% of the time. A significant saving in fan
horsepower can be achieved utilizing static pressure reset.
Third Party 4-20mA Input
— It is also possible to perform
static pressure reset via an external 4-20 mA signal connected
to the CEM board where 4 mA corresponds to 0 in. reset and
20 mA corresponds to 3 in. of reset. The only caveat to this is
that the static pressure 4-20 mA input shares the same input as
the analog OAQ sensor. Therefore, obviously both sensors cannot be used at the same time. To enable the static pressure reset
4-20 mA sensor: Set Configuration
UNITSENSSP.RS
to "Enabled."
Static Pressure Reset Sensor (
quality sensor is not configured (Configuration
SP.RS) — If the outdoor air
IAQ
AQ.CFOQ.A.C = 0), then it is possible to use that sensor's
location on the CEM board to monitor or perform static pressure reset via an external 4-20 mA input. Enabling this sensor
will give the user the ability to reset from 0 in. to 3 in. of static,
the supply static pressure setpoint (Configura-
tion
SP
SP.SP), where 4 mA= 0 in. and 20 mA = 3 inches.
As an example: If the static pressure reset input is measuring 6 mA, then the input is resetting 2 mA of its 16 mA (4-20)
"control range." This is essentially
2
/16 of 3 in. or 0.375 in. of
reset. If the static pressure setpoint (SP.SP) = 1.5 in., then the
static pressure control point for the system will be 1.5 - 0.375 =
1.125 inches.
ITEMEXPANSIONRANGEUNITSCCN POINTDEFAULT
Inputs
4-20 SP.MStatic Pressure mA4-20mASP_MA
4-20 SP.M.TStatic Pressure mA Trim-2.0 +2.0mASPMATRIM
GENERAL — The N Series ComfortLink controls offer the
capability to detect a failed supply fan through either a duct
static pressure transducer or an accessory discrete switch. The
fan status switch is an accessory that allows for the monitoring
of a discrete switch, which trips above a differential pressure
drop across the supply fan. But for any unit with an installed
duct static pressure sensor, it is possible to measure duct pressure rise directly, which removes the need for a differential
switch.
SETTING UP THE SYSTEM — There are two configurations of concern located in Configuration
UNIT. See
Table 48.
Table 48 — Fan Status Monitoring Configuration
ITEMEXPANSIONRANGECCN POINT
SFS.SFan Fail Shuts Down Unit Yes/NoSFS_SHUT
SFS.MFan Stat Monitoring Type 0 - 2SFS_MON
Fan Stat Monitoring Type (
SFS.M) — This configuration se-
lects the type of fan status monitoring to be performed.
0 - NONE — No switch or monitoring
1 - SWITCH — Use of the fan status switch
2 - SP RISE — Monitoring of the supply duct pressure.
Fan Fail Shuts Down Unit (
SFS.S) — This configuration
will allow whether the unit should shut down on a supply fan
status fail or simply alert the condition and continue to run.
YES — Shut down the unit if supply fan status monitoring
fails and send out an alarm.
NO — Do not shut down the unit if supply fan status monitoring fails but send out an alert.
SUPPLY FAN STATUS MONITORING LOGIC — Regardless of whether the user is monitoring a discrete switch or is
monitoring static pressure, the timings for both techniques are
the same and rely upon the configuration of static pressure
control.
The configuration which determines static pressure control
is Configuration
SP
SP.CF. If this configuration is set to 0
(none), a fan failure condition must wait 60 continuous seconds
before taking action. If this configuration is 1 (VFD), a fan failure condition must wait 3 continuous minutes before taking
action.
If the unit is configured to monitor a fan status switch
(SFS.M = 1), and if the supply fan commanded state does not
match the supply fan status switch for 3 continuous minutes,
then a fan status failure has occurred.
If the unit is configured for supply duct pressure monitoring
(SFS.M = 2), then
• If the supply fan is requested ON and the static pressure
reading is not greater than 0.2 in. wg for the time clarified
above, a fan failure has occurred.
• If the supply fan is requested OFF and the static pressure
reading is not less than 0.2-in. wg for the time clarified
above, a fan failure has occurred.
Dirty Filter Switch — This unit is equipped with several
filter stages. It is important to maintain clean filters to reduce the
energy consumption of the system. This unit is designed to provide several ways to achieve this goal. Table 49 shows the nine
configurations for filter monitoring in this unit. If the configuration for either the main or final filter is set to 0-Disable then the
input is set to read clean all the time. There are several controls
which need to be used in conjunction with the filter configuration so that each corresponding setting will operate correctly.
The fault status timer is a parameter which sets the number
of minutes the filter status must be in a fault state before the fault
latch is closed. To set the fault time use Configuration
IAQFLTCFS.FT the range is between 0 and 10 min-
utes. The default for this parameter is 2 minutes.
Filter types (MF_TYP, PF_TYP) and final resistance
(MF_FR, PF_FR) are used for the Delta Pressure and Predictive Life configurations for the main and post filter. The final resistance will be automatically set when the filter type is selected.
After selecting a filter type it is possible to change the filter final
resistance. Settings for filters based on Table 49 and 50 for main
and post filters.
Table 49 — Main Filter Types
MAIN FILTER TYPE
(MF_TYP)
0
1
2
3
4
5
6
7
8
9
DESCRIPTION
Std 2 in. MERV1
4 in. MERV 81
4 in. MERV 141.5
12 in. MERV 14
Bag with 2 in. pre’s
12 in. MERV 14
Bag with 4 in. pre’s
19 in. MERV 15
Bag with 2 in. pre’s
19 in. MERV 15
Bag with 4 in. pre’s
12 in. MERV 14
Cart with 2 in. pre’s
12 in. MERV 14
Cart with 4 in. pre’s
Strion Air2
MAIN FILTER FINAL
RESISTANCE
(MF_FR)
2
2
2
2
2.5
2.5
Table 50 — Final Filter Types
MAIN FILTER TYPE
(MF_TYP)
0
1
2
3
4
5
6
DESCRIPTION
None0
12 in. MERV 14
Cart with 2 in. pre’s
12 in. MERV 14
Cart with 4 in. pre’s
19 in. MERV 15
Bag with 2 in. pre’s
19 in. MERV 15
Bag with 4 in. pre’s
12 in. MERV 17
Bag with 2 in. pre’s
12 in. MERV 17
Bag with 4 in. pre’s
MAIN FILTER FINAL
RESISTANCE
(MF_FR)
2.5
2.5
2
2
3
3
To change the filter type for the main filter use Configuration
IAQFLTCMF.TY set between 0 and 6 according to
the main filter type table. To change the filter type for the final
filter use Configuration
IAQFLTCPF.TY set the be-
tween 0 and 6 according to the post filter type table. To adjust
the final resistance for the main filter after a filter type has been
selected use Configuration
IAQFLTCMF.FR and set
from 0 to 10. To adjust the final resistance for the post filter use
Configuration
IAQFLTCPF.FR and set between 0 and
10.
1 = Switch
— If the Filter configuration for either the main or
post filter is set to 1 (Switch) then a filter status switch should be
installed. The monitoring of the filters is based on a clean/dirty
switch input.
Monitoring of the main and post filter status switches is disabled in the Service Test mode and when the supply fan is not
commanded on. If the fan is on and the unit is not in a test mode
and either the main or post filter status switch reads "dirty for a
user set continuous amount of time, an alert is generated. Recovery from this alert is done through a clearing of all alarms or
after cleaning the filter and the switch reads clean for 30 seconds.
72
2 = Schedule
— Filter configuration for either main or post filter can be set to 2 (Schedule). In this mode the filter status is
based on a schedule set by the user. The status is determined by
the amount of time remaining in the filter life. The user sets the
lifetime for the filter in months from 1 to 60 (5 years). The default for this parameter is 12 months. It is also possible to set a
reminder and reset the schedule.
The main and post filters use "Birth points" and current date
to calculate filter life and filter reminder. The birth date and current date are expressed as the number of days since 1/1/2000.
To change the main filter life use Configura-
tion
IAQFLTCMF.LT and set to required filter life from
1 to 60 months. To change the post filter life use Configura-
tion
IAQFLTCPF.LT and set to required filter life from
1 to 60 months.
To set main filter life reminder use
tion
IAQFLTCMF.RM
and enter required filter reminder
from 0 to 60 months. To set post filter life reminder use
ration
IAQFLTCPF.RM
and enter required filter re-
Configura-
Configu-
minder from 0 to 60 months. Setting the reminder for either main
or post filter to 0 will disable the reminder function for that filter.
To reset the main filter status schedule use Configura-
tion
IAQFLTCMF.RS, when set to 'yes' the birth date
for the main filter will be converted to the current date in number of days since 1/1/2000. To reset the post filter status schedule use Configuration
IAQFLTCPF.RS, when set to
'yes' the birth date for the post filter will be converted to the current date in number of days since 1/1/2000.
3 = Delta Pressure
— Main and post filter status can be determined in relation to a maximum pressure differential across the
corresponding filter. The pressure difference is provided by a
transducer and sensors. The delta pressure configuration is disabled in Service Test mode and when the supply fan is not commanded on. If the fan is on, the unit is not in test mode and the
filter delta pressure is greater than or equal to the filter final resistance (MF_FR, PF_FR) for a period of time equal to the status fault timer (FS.FT) then an alarm will be generated. Recov-
ery from this alert is possible by clearing all alarms or by replacing the dirty filter and the delta pressure is less than the new
filters final resistance for more than 30 seconds.
4 = Predictive Life (Calculate and Learn)
— The filter status
can be determined through a predicted life. When clean filters
are first installed using this configuration they must be commissioned before use. This is done by setting the supply fan to a certain speed (in %) and measuring Supply Air CFM (SACFM)
versus delta pressure (MF.DP or PF.DP) across the filter. There
will need to be a maximum of 10 entries plus an entry for 0
SACFM and one for maximum SACFM. The data is collected
and stored by the control.
The 10 entries are separated into bins based on maximum
Supply Air CFM (SACFM). Maximum SACFM is based on
unit size and supply fan SACFM configuration (SCFM_CFG)
view Table 51.
Table 51 — Maximum SACFM
UNIT SIZESCFM_CFGMAX_SACFM
75, 90, 105
120, 130, 150
75, 90, 105, 120, 130, 150
LOW FAN40,000
LOW FAN50,000
HIGH FAN60,000
During runtime the SACFM is used to interpolate the baseline pressure. The interpolation is then used to calculate the filter
status. See Table 52.
It is possible to reset the main filter predictive life table and the
post filter predictive life table separately. To reset the main filter
predictive life table use
and select yes. To reset the post filter predictive life table use
figuration
IAQFLTCPFT.R
ConfigurationIAQFLTCMFT.R
Con-
and select yes.
5 = Predictive Life (Calculate only) — Once the control has
learned the life of the filter it is possible to set the control to use
the learned information to calculate the life of filters used in the
future. This is only an option when the replacement filters used
are the same type and final resistance as the filters used to learn
the life.
Table 52 — Dirty Filter Switch Points
ITEMEXPANSIONRANGE
Main Filter Status
Configuration
Configuration
FLTCMFL.S
Configuration
FLTCPFL.S
InputsGEN.I
FLT.S
InputsGEN.I
PFL.S
Post Filter Status
Configuration
Filter Status Input DRTY/CLNFLTS
Filter Status Input DRTY/CLNPFLTS
0 - Disable
1 - S w i t c h
2 - Schedule
3 - Delta Pressure
4 - Calculate and
Learn
5 - Calculate Only
0 - Disable
1 - S w i t c h
2 - Schedule
3 - Delta Pressure
4 - Calculate and
Learn
5 - Calculate Only
CCN
POINT
FLTS_ENA
PFLS_ENA
Economizer — The N Series economizer damper is con-
trolled by communicating actuators motor over the local equipment network (LEN) and is connected directly to linkage in the
economizer section.
Economizers are used to provide ventilation air as well as
free cooling based on several configuration options. This section shall be devoted to a description of the economizer and its
ability to provide free cooling. Please see the section on Indoor
Air Quality for more information on setting up and using the
economizer to perform demand controlled ventilation (DCV)
via the controlling of its minimum position. Also, please see
the Third Party Control interface section for a description on
how to take over the operation of the economizer through external control.
The N Series controls have the capability to not only control an economizer but also to report its health and operation
both to the local display and CCN network. Also, through either the local display or the CCN, the service technician has additional diagnostic tools at his/her disposal to predict the state
of the economizer.
ECONOMIZER FAULT DETECTION AND DIAGNOSTICS (FDD) CONTROL — The Economizer Fault Detection
and Diagnostics control can be divided into two tests: test for
mechanically disconnected actuator and test for stuck/jammed
actuator.
Mechanically Disconnected Actuator
chanically disconnected actuator shall be performed by monitoring SAT as the actuator position changes and the damper
blades modulate. As the damper opens, it is expected SAT will
drop and approach OAT when the damper is at 100%. As the
damper closes, it is expected SAT will rise and approach RAT
when the damper is at 0%. The basic test shall be as follows:
1. With supply fan running take a sample of SAT at current
actuator position.
2. Modulate actuator to new position.
3. Allow time for SAT to stabilize at new position.
4. Take sample of SAT at new actuator position and determine:
a. If damper has opened, SAT should have decreased.
b. If damper has closed, SAT should have increased.
5. Use current SAT and actuator position as samples for next
comparison after next actuator move.
— The test for a me-
73
The control shall test for a mechanically disconnected damper
if all the following conditions are true:
1. An economizer is installed.
2. The supply fan is running.
3. Conditions are good for economizing.
4. The difference between RAT and OAT > T24RATDF. It
is necessary for there to be a large enough difference between RAT and OAT in order to measure a change in
SAT as the damper modulates.
5. The actuator has moved at least T24ECSTS %. A very
small change in damper position may result in a very
small (or non-measurable) change in SAT.
6. At least part of the economizer movement is within the
range T24TSTMN% to T24TSTMX%. Because the mixing of outside air and return air is not linear over the entire
range of damper position, near the ends of the range even
a large change in damper position may result in a very
small (or non-measurable) change in SAT.
Furthermore, the control shall test for a mechanically disconnected actuator after T24CHDLY minutes have expired when
any of the following occur (this is to allow the heat/cool cycle
to dissipate and not influence SAT):
1. The supply fans switches from OFF to ON.
2. Mechanical cooling switches from ON to OFF.
3. Reheat switches from ON to OFF.
4. The SAT sensor has been relocated downstream of the
heating section and heat switches from ON to OFF.
The economizer shall be considered moving if the reported
position has changed at least +/- T24ECMDB %. A very small
changed in position shall not be considered movement.
The determination of whether the economizer is mechanically disconnected shall occur SAT_SEC/2 seconds after the
economizer has stopped moving. The control shall log a
"damper not modulating" alert if:
1. SAT has not decreased by T24SATMD degrees F
SAT_SET/2 seconds after opening the economizer at
least T24ECSTS%, taking into account whether the entire
movement has occurred within the range 0T24TSTMN%.
2. SAT has not increased by T24SATMD degrees F
SAT_SET/2 seconds after closing the economizer at least
T24ECSTS%, taking into account whether the entire
movement has occurred within the range T24TSTMX100%..
3. Economizer reported position <=5% and SAT is not approximately equal to RAT. SAT not approximately equal
to RAT shall be determined as follows:
a. SAT<RAT-(2*2(thermistor accuracy) + 2 (SAT
increase due to fan)) or
b. SAT>RAT+(2*2(thermistor accuracy) + 2 (SAT
increase due to fan))
4. Economizer reported position >=95% and SAT is not approximately equal to OAT. SAT not approximately equal
to OAT shall be determined as follows:
a. SAT<OAT-(2*2(thermistor accuracy) + 2 (SAT
increase due to fan)) or
b. SAT>OAT+(2*2(thermistor accuracy) + 2 (SAT
increase due to fan))
Except when run as part of a self-test, the control shall not
automatically clear "damper not modulating" alerts on units.
Test for stuck/jammed actuator
— The control shall test for a
jammed actuator as follows:
• If the actuator has stopped moving and the reported position (ECONxPOS, where x is 1,2) is not within ±
EC_FLGAP% of the command position (ECONOCMD)
after EC_FLTMR seconds, a "damper stuck or jammed"
alert shall be logged, i.e. abs(ECONxPOS ECONODMD) > EC_FLGAP for a continuous time
period EC_FLTMR seconds.
• If the actuator jammed while opening (i.e., reported position < commanded position), a "not economizing when it
should" alert shall be logged.
• If the actuator jammed while closing (i.e., reported position > command position), the "economizing when it
should not" and "too much outside air" alerts shall be
logged.
The control shall automatically clear the jammed actuator
alerts as follows:
• If the actuator moves at least 1%, the alerts shall be
cleared.
Alternate Excess Outdoor Air Test
— For units configured
with outdoor air measuring stations (OCFMSENS=YES):
Configuration
ECONCFM.COCF.S=YES
Under the following conditions:
1. Unit is not performing free cooling
2. OACFM sensor is detected as good
3. IAQ is not overriding CFM
4. Purge is not overriding CFM
If OACFM > (ECMINCFM + EX_ARCFM) for
EX_ARTMR seconds the "excess outside air" alert shall be
logged.
DIFFERENTIAL DRY BULB CUTOFF CONTROL
Differential Dry Bulb Changeover
— As both return air and
outside air temperature sensors are installed as standard on
these units, the user may select this option, E.SEL = 1, to perform a qualification of return and outside air in the enabling/
disabling of free cooling. If this option is selected the outside
air temperature shall be compared to the return-air temperature
to dis-allow free cooling as shown Table 53:
Table 53 — Differential Dry Bulb Cutoff Control
E.SEL (ECON_SEL)
NONE,
OUTDR.ENTH,
DIF.ENTHALPY
DIFF.DRY BULB
DDB.C
(EC_DDBCO)
N/AN/ANO
0 degFOAT>RATYES
–2 degFOAT>RAT-2 YES
–4 degFOAT>RAT-4 YES
–6 degFOAT>RAT-6 YES
OAT/RAT
Comparison
OAT<=RATNO
OAT<=RAT-2 NO
OAT<=RAT-4 NO
OAT<=RAT-6 NO
(DDBCSTAT)
DDBC
The status of differential dry bulb cutoff shall be visible un-
der Run Status
ECONDISADDBC.
There shall be hysteresis where OAT must fall 1 deg F lower than the comparison temperature when transitioning from
DDBCSTAT=YES to DDBSTAT=NO.
ECONOMIZER SELF TEST — It is possible for one actuator to become mechanically disconnected while the other(s)
continue to work properly, the following self-test utilizes fan
characteristics and motor power measurements to determine
whether the dampers are properly modulating. A fan that is
moving more air uses additional power than a fan that is moving a lesser quantity of air. In this test, each actuator/damper assembly is commanded independently while the fan and motor
characteristics are monitored.
74
It shall be possible to manually start the self-test:
• In Navigator display, this test shall be located at Service
Te st
AC.DTEC.TS.
• Running the test shall require setting Service
Te st
TEST=ON
The test shall also automatically run based on EC.DY
(T24_ECDY) and EC.TM (T24_ECTM):
• If conditions are acceptable to run the self-test (see
below), the test shall be automatically started on the configured day EC.DY (T24_ECDY) at the configured time
EC.TM (T24_ECTM).
• If conditions are not acceptable to run the self-test, it
shall be re-scheduled for 24 hours later.
The economizer self-test shall only be allowed run if all of the
following conditions are valid:
1. The economizer is enabled
2. No actuators are detected as stuck
3. No actuators are detect as unavailable
4. RCB1 is properly communicating
5. The unit not down due to failure (A152)
6. The supply fan VFD is not in bypass mode (if unit has
this option)
7. If configured for building pressure, the unit has an return
fan VFD and the fan is not in bypass mode
In addition to the above conditions, the economizer self-test
shall not be automatically run if any of the following conditions are valid:
1. Unit not in OFF or VENT mode.
The Test screen should be similiar to the following:
EC.TR ON
1. Command all actuators and dampers to the closed posi-
tion.
2. Run the fan at T24SFSPD for T24ACMRT minutes and
take a baseline torque (VFD1TMAV) measurement. With
the dampers closed, there will be the least amount of airflow, and therefore the least amount of motor torque.
3. Modulate a single actuator/damper assembly open to
T24ACOPN. This will increase the airflow.
4. Let the motor run for one minute. If the torque has in-
creased by T24VFDPC % over the baseline measurement
from Step 2, the current torque is set as the new baseline
measurement and proceed to Step 5. If the torque has not
increased by T24VFDPC % continue to run the fan for a
total of T24ACMRT minutes. If, after T24ACMRT minutes total, the torque has not increased by T24VFDPC %
over the Step 2 baseline measurement, a fault is logged,
and the test is ended.
5. Modulate the actuator/damper assembly closed.
6. Let the motor run for one minute. If the torque has de-
creased by T24VFDPC % over the baseline measurement
from Step 4, the current torque is set as the new baseline
measurement and proceed to Step 7. If the torque has not
decreased by T24VFDPC % continue to run the fan for a
total of T24ACMRT minutes. If, after T24ACMRT minutes total, the torque has not decreased by T24VFDPC %
below the Step 4 baseline measurement, a fault is logged,
and the test is ended.
7. Repeat Steps 1-5 for additional actuator/damper assemblies.
8. Command actuators/dampers to "normal" positions.
If the torque increases and decreases properly,
EC.ST="PASS", otherwise EC.ST="FAIL".
If EC.ST is set to pass, any existing "damper not modulat-
ing" alert shall be automatically cleared.
If EC.ST is set to fail, the "damper not modulating" alert
shall be logged.
If at any point in the test the fan does not reach the command speed or an actuator does not reach the command position within five minutes, the test shall be stopped and the status
set to "NOT RUN."
FDD CONFIGURATIONS
Log Title 24 Faults (LOG.F) — Enables Title 24 detection
and logging of mechanically disconnected actuator faults.
T24 Econ Move Detect
(EC.MD) — Detects the amount of
change required in the reported position before economizer is
detected as moving.
T24 Econ Move SAT Test
(EC.ST) — The minimum
amount the economizer must move in order to trigger the test
for a change in SAT. The economizer must move at least
EC.ST % before the control will attempt to determine whether
the actuator is mechanically disconnected.
T24 Econ Move SAT Change
(S.CHG) — The minimum
amount (in degrees F) SAT is expected to change based on
economizer position change of EC.ST.
T24 Econ RAT-OAT Diff
(E.SOD) — The minimum amount
(in degrees F) between RAT (if available) or SAT (with economizer closed and fan on) and OAT to perform mechanically
disconnected actuator testing.
T24 Heat/Cool End Delay
(E.CHD) — The amount of time
(in minutes) to wait before mechanical cooling or heating has
ended before testing for mechanically disconnected actuator.
This is to allow SAT to stabilize at conclusion of mechanical
cooling or heating.
T24 Test Minimum Position
(ET.MN) — The minimum po-
sition below which tests for a mechanically disconnected actuator will not be performed. For example, if the actuator moves
entirely within the range 0 to ET.MN a determination of
whether the actuator is mechanically disconnected will not be
made. This is due to the fact that at the extreme ends of the actuator movement, a change in position may not result in a detectable change in temperature. When the actuator stops in the
range 0 to 2% (the actuator is considered to be closed), a test
shall be performed where SAT is expected to be approximately
equal to RAT. If SAT is not determined to be approximately
equal to RAT, a “damper not modulating” alert shall be logged.
T24 Test Maximum Position
(ET.MX) — The maximum po-
sition above which tests for a mechanically disconnected actuator will not be performed. For example, if the actuator moves
entirely within the range ET.MX to 100 a determination of
whether the actuator is mechanically disconnected will not be
made. This is due to the fact that at the extreme ends of the actuator movement, a change in position may not result in a detectable change in temperature. When the actuator stops in the
range 98 to 100% (the actuator is considered to be open), a test
shall be performed where SAT is expected to be approximately
equal to OAT. If SAT is not determined to be approximately
equal to OAT, a “damper not modulating” alert shall be logged.
SAT Settling Time
(SAT.T) — The amount of time (in sec-
onds) the economizer reported position must remain unchanged (± EC.MD) before the control will attempt to detect a
mechanically disconnected actuator. This is to allow SAT to
stabilize at the current economizer position. This configuration
sets the settling time of the supply-air temperature (SAT). This
typically tells the control how long to wait after a stage change
75
before trusting the SAT reading, and has been reused for Title
24 purposes.
Economizer Deadband Temp
deadband between measured SAT and calculated SAT when
performing economizer self-test. Range is 0-10, default is 4.
Econ Fault Detect Gap
tween actuator command and reported position in %. Used to
detect actuator stuck/jammed. Range is 2-100, default is 5.
Econ Fault Detect Timer
fault detection in seconds. Used to detect actuator stuck/
jammed. Range is 10-240, default is 20.
Excess Air CFM
CFM. Used to detect excess outside air. Range is 400-4000, default is 800.
Excess Air Detect Timer
air detection with a range of 30-240. Default is 150.
Econ Auto-Test Day (
form automatic economizer test. Range=NEVER, MON, TUE,
WED, THR, FRI, SAT, SUN. Default is SAT.
Econ Auto=Test Time (
form automatic economizer test. The range is 0-23, default is 2.
T24 AutoTest SF Run Time
run supply fan before sampling torque or making torque comparison. Range is 1 to 10, default is 2.
T24 Auto-Test VFD Speed
during economizer auto-component test. Range is 10 to 50, default is 20.
T24 Auto-Test Econ % Open (
each economizer during auto-component test. Range is 1 to
100. Default is 30.
T24 Auto-Test VFD % Change
change in torque when damper opens from 0 to AC.OP and
then from AC.OP to 0. Range is 1 to 20, default is 10.
SETTING UP THE SYSTEM — The economizer configuration options are under the Local Display Mode Configura-
tion
ECON. See Table 54.
ECONOMIZER OPERATION
Is Economizer Enabled?
used or is to be completely disabled the configuration option
EC.EN may be set to NO. Otherwise the economizer enabled
configuration must be set to YES. Without the economizer enabled, the outdoor-air dampers will open to minimum position
when the supply fan is running. Outdoor-air dampers will
spring-return closed upon loss of power or shutdown of the
supply fan.
What is the Economizer Minimum Position?
uration option EC.MN is the economizer minimum position.
See the section on Indoor Air Quality for further information
on how to reset the economizer even further to gain energy savings and to more carefully monitor "indoor IAQ problems."
What is the Economizer Maximum Position?
limit of the economizer may be clamped if so desired via configuration option EC.MX.
It defaults to 98% to avoid problems associated with slight
changes in the economizer damper's end stop over time. Typically this will not need to be adjusted.
What is Economizer Trim for Sum Z?
simple explanation. Sum Z stands for the adaptive cooling
(X.CFM) — The max allowed excess air in
(AC.EC) — The allowed
(E.GAP) — The discrepancy be-
(E.TMR) — The timer for actuator
(X.TMR) — The timer for excess
EC.DY) — The day on which to per-
EC.TM) — The time at which to per-
(AC.MR) — Amount of time to
(AC.SP) — Speed to run VFD
AC.OP) — Amount to open
(VF.PC) — Expected
— If an economizer is not being
— The config-
— The upper
— A strange title but a
control algorithm used for multiple stages of compression. The
configuration option, E.TRM is typically set to Yes, and allows
the economizer to modulate to the same control point "Sum Z"
uses to control compressor staging. The advantage is lower
compressor cycling coupled with tighter temperature control.
Setting this option to "No" will cause the economizer, if it is indeed able to provide free cooling, to open to the Economizer
Max. Position (EC.MX) during mechanical cooling.
ECONOMIZER CHANGEOVER SELECTION — There
are four potential elements at play which may run concurrently
which determine whether the economizer is able to provide
free cooling:
• Dry Bulb Changeover (outside air temperature qualification)
• The Enthalpy Switch (discrete switch input monitoring)
Dry Bulb Changeover
viewed under TemperaturesAIR.TOAT.
The control constantly compares its outside-air temperature
reading against OAT.L. If the temperature reads above OAT.L,
the economizer will not be allowed to perform free cooling.
NOTE: If the user wishes to disable the enthalpy switch from
running concurrently, a field-supplied jumper must be installed
between TB201 terminals 3 and 4.
Enthalpy Switch
viewed under Inputs
installed as standard on all N Series rooftops. When the switch
reads HIGH, free cooling will be disallowed.
The enthalpy switch opens* when the outdoor enthalpy is
above 24 Btu/lb or dry bulb temperature is above 70 F and will
close when the outdoor enthalpy is below 23 Btu/lb or the dry
bulb temperature is below 69.5 F.
There are two jumpers under the cover of the enthalpy
switch. One jumper determines the mode of the enthalpy
switch/receiver. The other is not used. For the enthalpy switch,
the factory setting is M1 and should not need to be changed.
The enthalpy switch may also be field converted to a differ-
ential enthalpy switch by field installing an enthalpy sensor
(33CSENTSEN or HL39ZZ003). The enthalpy switch/receiver
remains installed in its factory location to sense outdoor air enthalpy. The additional enthalpy sensor is mounted in the return
air stream to measure return air enthalpy. The enthalpy control
jumper must be changed from M1 to M2 for differential enthalpy control. For the return air enthalpy sensor, a "two wire" sensor, connect power to the Vin input and signal to the 4-20 loop
input.
It should be noted that there is another way to accomplish
differential enthalpy control when both an outdoor and return
air relative humidity sensor are present. See section on Economizer Changeover Select for further information.
*NOTE: The enthalpy switch has both a low and a high output.
To use this switch as designed the control must be connected to
the "low" output. Additionally there is a "switch logic" setting
for the enthalpy switch under ConfigurationSW.LGENT.L. This setting must be configured to closed
(CLSE) to work properly when connected to the low output of
the enthalpy switch.
— Outside-air temperature may be
— The state of the enthalpy switch can be
GEN.IENTH. Enthalpy switches are
IAQ
76
Table 54 — Economizer Configuration Table
ITEMEXPANSIONRANGEUNITSCCN POINTDEFAULT
EC.ENEconomizer Installed?Yes/NoECON_ENAYes
EC.MNEconomizer Min.Position0 - 100%ECONOMIN5
EC.MXEconomizer Max.Position0 - 100%ECONOMAX98
E.TRMEconomzr Trim For SumZ ?Yes/NoECONTRIMYes
E.SELEcon ChangeOver Select0 - 3ECON_SEL0
DDB.C
OA.E.COA Enthalpy ChgOvr Selct1 - 5OAEC_SEL4
OA.ENOutdr.Enth Compare Value18 - 28OAEN_CFG24
OAT.LHigh OAT Lockout Temp55 - 120dFOAT_LOCK60
O.DE WOA Dewpoint Temp Limit50 - 62dFOADEWCFG55
ORH.SOutside Air RH SensorEnable/DisableOARHSENSDisable
CFM.COUTDOOR AIR CFM CONTROL
OCF.SOutdoor Air CFM SensorEnable/DisableOCFMSENSDisable
O.C.MXEconomizer Min.Flow0 - 20000CFMOACFMMAX2000
O.C.MNIAQ Demand Vent Min.Flow0 - 20000CFMOACFMMIN0
O.C.DBEcon.Min.Flow Deadband200 - 1000CFMOACFM_DB400
E.CFGECON.OPERATION CONFIGS
E.P.GNEconomizer Prop.Gain0.7 - 3.0EC_PGAIN1
E.RNGEconomizer Range Adjust0.5 - 5^FEC_RANGE2.5
E.SPDEconomizer Speed Adjust0.1 - 10EC_SPEED0.75
E.DBDEconomizer Deadband0.1 - 2^FEC_DBAND0.5
UEFCUNOCC.ECON.FREE COOLING
FC.CFUnoc Econ Free Cool Cfg0-2UEFC_CFG0
FC.TMUnoc Econ Free Cool Time0 - 720minUEFCTIME120
FC.L.OUn.Ec.Free Cool OAT Lock40 - 70dFUEFCNTLO50
ACT.CECON.ACTUATOR CONFIGS
SN.1.1Econ Serial Number 10 - 255ECON_SN10
SN.1.2Econ Serial Number 20 - 255ECON_SN20
SN.1.3Econ Serial Number 30 - 255ECON_SN30
SN.1.4Econ Serial Number 40 - 255ECON_SN40
SN.1.5Econ Serial Number 50 - 255ECON_SN50
C.A.L1Econ Ctrl Angle Lo Limit0 - 90ECONCALM85
SN.2.1Econ 2 Serial Number 10 - 255ECN2_SN10
SN.2.2Econ 2 Serial Number 20 - 255ECN2_SN20
SN.2.3Econ 2 Serial Number 30 - 255ECN2_SN30
SN.2.4Econ 2 Serial Number 40 - 255ECN2_SN40
SN.2.5Econ 2 Serial Number 50 - 255ECN2_SN50
C.A.L2Econ 2 Ctrl Angle Lo Limit0 - 90ECN2CALM85
SN.3.1Econ 3 Serial Number 10 - 255ECN3_SN10
SN.3.2Econ 3 Serial Number 20 - 255ECN3_SN20
SN.3.3Econ 3 Serial Number 30 - 255ECN3_SN30
SN.3.4Econ 3 Serial Number 40 - 255ECN3_SN40
SN.3.5Econ 3 Serial Number 50 - 255ECN3_SN50
C.A.L3Econ 3 Ctrl Angle Lo Limit0 - 90ECN3CALM85
T.24.CTITLE 24 CONFIGS
LOG.FLog Title 24 FaultsYes/NoT24LOGFLNo
EC.MDT24 Econ Move Detect1 - 10T24ECMDB1
EC.STT24 Econ Move SAT Test10 - 20T24ECSTS10
S.CHGT24 Econ Move SAT Change0 - 5T24SATMD0.2
E.SODT24 Econ RAT-OAT Diff5 - 20T24RATDF15
E.CHDT24 Heat/Cool End Delay0 - 60T24CHDLY25
ET.MNT24 Test Minimum Pos.0 - 50T24TSTMN15
ET.MXT24 Test Maximum Pos.50 - 100T24TSTMX85
SAT.TSAT Settling Time10 - 900SAT_SET240
AC.ECEconomizer Deadband Temp0 - 10AC_EC_DB4
E.GAPEcon Fault Detect Gap2 - 100EC_FLGAP5
E.TMREcon Fault Detect Timer10 - 240EC_FLTMR20
X.CFMExcess Air CFM400 - 4000EX_ARCFM800
X.TMRExcess Air Detect Timer30 - 240EX_ARTMR150
AC.MRT24 AutoTest SF Run Time1 - 10T24ACMRT2
AC.SPT24 Auto-Test VFD Speed10 - 50T24ACSPD20
AC.OPT24 Auto-Test Econ % Opn1 - 100T24ACOPN30
VF.PCT24 Auto-Test VFD % Chng1 - 20T24VFDPC10
— The control is capable of
performing any one of the following changeover types in addition to both the dry bulb lockout and the discrete switch input:
— As both return air and
outside air temperature sensors are installed as standard on
these units, the user may select this option, E.SEL = 1, to per-
form a qualification of return and outside air in the enabling/
disabling of free cooling. If this option is selected and outsideair temperature is greater than return-air temperature, free cooling will not be allowed.
Outdoor Enthalpy Changeover
— This option should be used
in climates with higher humidity conditions. Unlike most control systems that use an enthalpy switch or enthalpy sensor, the
N Series units can use the standard installed outdoor dry bulb
sensor and an accessory relative humidity sensor to calculate
the enthalpy of the air.
Setting E.SEL = 2, requires that the user configure OA.E.C,
the "Outdoor Enthalpy Changeover Select" configuration item,
install an outdoor relative humidity sensor and to make sure a
control expansion module board (CEM) is present. Once the
sensor and board are installed, all the user need do is to enable
ORH.S, the outdoor relative humidity sensor configuration option. This in turn will enable the CEM board to be read, if it is
not so already, automatically.
NOTE: If the user wishes to disable the enthalpy switch from
running concurrently, a field-supplied jumper must be installed
between TB201 terminals 3 and 4.
Differential Enthalpy Changeover
— This option compares
the outdoor air enthalpy to the return air enthalpy and favors
the airstream with the lowest enthalpy. This option should be
used in climates with high humidity conditions. This option
uses both humidity sensors and dry bulb sensors to calculate
the enthalpy of the outdoor and return air. An accessory outdoor air humidity sensor (ORH.S) and return air humidity sen-
sor (RRH.S) are used. The outdoor air relative humidity sensor
configuration (ORH.S) and return air humidity sensor configu-
ration (Configuration
SENSRRH.S) must be enabled.
NOTE: If the user wishes to disable the enthalpy switch from
running concurrently, a field-supplied jumper must be installed
between TB201 terminals 3 and 4.
Outdoor Dewpoint Limit Check
— If an outdoor relative humidity sensor is installed, the control is able to calculate the
outdoor air dewpoint temperature and will compare this temperature against the outside air dewpoint temperature limit configuration (O.DEW).
If the outdoor air dewpoint temperature is greater than
O.DEW, "free cooling" will not be allowed.
Custom Psychrometric Curves
— See Figure 16 for an exam-
ple of a custom curve constructed on a psychrometric chart.
Configuring the Economizer to Communicate Via Actuator
"Serial Number" — Every actuator used in the N Series control system has its own unique serial number. The rooftop control uses this serial number to communicate with the actuator
over the local equipment network (LEN). These serial numbers
are programmed at the factory and should not need changing.
Should field replacement of an actuator become necessary, it
will be required to configure the serial numbers of the new actuator. Five individual numbers make up this serial number and
these can be programmed to match the serial number of the actuator in its "Economizer Actuator Configs" group, ACT.C.
(SN.1.1, SN.1.2, SN.1.3, SN.1.4, SN.1.5, SN.2.1, SN.2.2,
NOTE: The serial numbers for all "LEN" actuators can be
found inside the control doors of the unit as well as on the actuator itself. If an actuator is replaced in the field, it is a good
idea to remove the additional peel off serial number sticker on
the actuator and cover up the old one inside the control doors.
35
35
40
45
40 45
10
DEWPOINT TEMPERATURE
60
55
50
50 55
65
6065
15
70
75
70 75
80
90%
80%
85
70%
60%
50%
40%
30%
20%
10%
8085
ENTHALPY
RELATIVE HUMIDITY
9095
2025
100 105
110
DRY BULB TEMPERATURE
115
50
45
40
35
30
78
Control Angle Alarm Configuration
tuator learns what its end stops are though a calibration at the
factory. Field-installed actuators may be calibrated in the Service Test mode. When an actuator learns its end stops through
calibration, internally it remembers what its "control angle" is.
From that moment on, the actuator will resolve this control angle and express its operation in a percent (%) of this "learned
range."
If the economizer has not learned a "sufficient" or "large
enough" control angle during calibration, the economizer
damper will be unable to control ventilation and free cooling,
For this reason the economizer actuator used in the N Series
control system has a configurable "control angle" alarm low
limit in its "Economizer Actuator Configs" group, ACT.C.
(C.A.L1, C.A.L2, C.A.L3). If the control angle learned through
calibration is less than C.A.L1, C.A.L2, or C.AL3, an alert will
occur and the actuator will not function.
NOTE: This configuration does not typically need adjustment.
It is configurable for the small number of jobs which may
require a custom solution or workaround.
UNOCCUPIED ECONOMIZER FREE COOLING — This
"Free Cooling" function is used to start the supply fan and use
the economizer to bring in outside air when the outside temperature is cool enough to pre-cool the space. This is done to delay
the need for mechanical cooling when the system enters the occupied period. Once the space has been sufficiently cooled during this cycle, the fan will be stopped.
In basic terms, the economizer will modulate in an unoccupied period and attempt to maintain space temperature to the
"occupied" cooling set point. This necessitates the presence of
a space temperature sensor.
Configuring the economizer for Unoccupied Economizer
Free Cooling is done in the UEFC group. Here you will find
three configuration options, FC.CF, FC.TM and FC.LO re-
spectively.
Unoccupied Economizer Free Cooling Configuration
(FC.CF) — This option is used to configure the "type" of unoccupied economizer free cooling control that is desired.
0 = disable unoccupied economizer free cooling
1 = perform unoccupied economizer free cooling as available
during the entire unoccupied period.
2 = perform unoccupied economizer free cooling as available,
FC.TM minutes before the next occupied period.
Unoccupied Economizer Free Cooling Time Configuration
(FC.TM) — This option is a configurable time period, prior to
the "next occupied period," that the control will allow unoccupied economizer free cooling to operate. This option is only applicable when FC.CF = 2.
Unoccupied Economizer Free Cooling Lockout
Temperature (FC.LO) — This configuration option allows the
user to select an outside air temperature, that below which unoccupied free cooling is disallowed. This is further explained in
the logic section.
Unoccupied Economizer Free Cooling Logic
qualifications that must be in order for unoccupied free cooling
to operate.
• Unit configured for an economizer
• Unit in the unoccupied mode
• FC.CF set to 1 or FC.CF set to 2 and within FC.TM
minutes of the next occupied period
• Not in the Temperature Compensated Start Mode
• Not in a cooling mode
• Not in a heating mode
• Not in a tempering mode
• Space temperature sensor enabled and sensor reading
healthy
— The economizer ac-
— There are
• Outside air temperature sensor healthy
• The economizer would be allowed to cool if the fan were
requested and in a cool mode.
• OAT > FC.LO ( 1.0 dF hysteresis applied)
• The rooftop is not in a fire smoke mode
• No fan failure when configured to shut the unit down on
a fan failure
If all of the above conditions are satisfied:
Unoccupied Economizer Free Cooling shall start when both
of the following conditions are true:
{SPT > (OCSP + 2)} AND {SPT > (OAT + 8)}
The Night Time Free Cooling Mode shall stop when either
of the following conditions are true:
{SPT < OCSP} OR {SPT < (OAT + 3)}
…where SPT = Space Temperature and OCSP = Occupied
Cooling Setpoint
When the Unoccupied Economizer Free Cooling mode is
active, the supply fan is turned on and the economizer damper
modulated to control to the supply air setpoint (Set-
points
(Inputs
OUTDOOR AIR CFM CONTROL — If an outdoor air cfm
flow station has been installed on a N Series rooftop, the economizer is able to provide minimum ventilation based on CFM,
instead of damper position. The Outdoor Air CFM reading can
be found in Inputs
control:
Outdoor Air CFM Sensor Enable (
enabled the outdoor air cfm sensor will be read and outside air
cfm control will be enabled.
Economizer Minimum Flow Rate (
configuration option replaces the Economizer Minimum Position (EC.MN) when the outdoor air cfm sensor is enabled.
IAQ Demand Vent Minimum Flow Rate (
"CFM" configuration option replaces the IAQ Demand Ventilation Minimum Position (ConfigurationIAQ.M) when the outdoor air cfm sensor is enabled.
Economizer Minimum Flow Deadband (
"CFM" configuration option defines the deadband of the CFM
control logic.
tain amount of CFM at any time for ventilation purposes. If the
outdoor air cfm measured is less than the current calculated
CFM minimum position, then the economizer will attempt to
open until the outdoor air cfm is greater than or equal to this
cfm minimum position. Now, this configurable deadband helps
keeps the economizer from attempting to close until the outdoor air cfm rises to the current minimum cfm position PLUS
the deadband value. Increasing this deadband value may help
to slow down excessive economizer movement when attempting to control to a minimum position at the expense of bringing
in more ventilation air then desired.
ECONOMIZER OPERATION CONFIGURATIONS
(WHICH AFFECT FREE COOLING ACTUATOR MODULATION) — There are configuration items in the E.CFG
menu group that affect how the economizer modulates when
attempting to follow an economizer cooling set point. Typically, they will not need adjustment. In fact, it is strongly advised
not to adjust these configurations from their default settings
without first consulting a service engineering representative.
algorithm is designed to automatically slow down the economizer actuator's rate of travel as outside-air temperature decreases. See Table 55.
SASP) plus any supply air reset that may be applied
RSETSA.S.R).
CFMO.CFM .
The following options are used to program outside air cfm
OCF.S) — If this option is
O.C.MX) — This "CFM"
O.C.MN) — This
IAQDCV.C
O.C.DB) — This
During CFM control, the economizer must guarantee a cer-
In addition, it should be noted that the economizer cooling
79
Table 55 — Economizer Run Status Table
ITEMEXPANSIONRANGEUNITSCCN POINTWRITE STATUS
EC1.PEconomizer 1 Out Act. Curr. Pos.0-100%ECONOPOS
EC2.PEconomizer 2 Ret. Act.Curr.Pos.0-100%ECON2POS
EC3.PEconomizer 3 Out Act.Curr.Pos.0-100%ECON3POS
ECN.CEconomizer Out Act.Cmd.Pos.0-100%ECONOCMDforcible
ACTVEconomizer Active ?YES/NOECACTIVE
DISAECON DISABLING CONDITIONS
UNV.1Econ Out Act. Unavailable?YES/NOECONUNAV
UNV.2Econ2 Ret Act. Unavailable?YES/NOECN2UNAV
UNV.3Econ3 Out Act. Unavailable?YES/NOECN3UNAV
ENTHEnth. Switch Read High ?YES/NOENTH
DBCDBC - OAT Lockout?YES/NODBC_STAT
DEWDEW - OA Dewpt.Lockout?YES/NODEW_STAT
DDBCDDBD- OAT > RAT Lockout?YES/NODDBCSTAT
OAECOAEC- OA Enth Lockout?YES/NOOAECSTAT
DECDEC - Diff.Enth.Lockout?YES/NODEC_STAT
EDTEDT Sensor Bad?YES/NOEDT_STAT
OATOAT Sensor Bad ?YES/NOOAT_STAT
FORCEconomizer Forced ?YES/NOECONFORC
SFONSupply Fan Not On 30s ?YES/NOSFONSTAT
CLOFCool Mode Not In Effect?YES/NOCOOL_OFF
OAQLOAQ Lockout in Effect ?YES/NOOAQLOCKD
HELDEcon Recovery Hold Off?YES/NOECONHELD
DH.DSDehumid. Disabled Econ.?YES/NODHDISABL
O.AIROUTSIDE AIR INFORMATION
OATOutside Air TemperaturedFOATforcible
OA.RHOutside Air Rel. Humidity%OARHforcible
OA.EOutside Air EnthalpyOAE
OA.D.TOutside Air Dewpoint TempdFOADEWTMP
ECONOMIZER DIAGNOSTIC HELP — Because there are
so many conditions which might disable the economizer from
being able to provide free cooling, the control offers a handy
place to identify these potentially disabling sources. All the
user has to do is check ACTV, the "Economizer Active" flag. If
this flag is set to "Yes" there is no reason to explore the group
under DISA, the "Economizer Disabling Conditions." If the
flag is set to "No," this means that at least one or more of the
flags under the group DISA are set to "Yes" and the user can
easily discover exactly what is preventing the economizer from
performing "free cooling."
In addition, the economizer's reported and commanded positions are viewable as well as one convenient place to view
outside-air temperature, relative humidity, enthalpy and dew
point temperature.
The following information can be found under the local display mode Run Status
Economizer Control Point Determination Logic
ECON.
— Once the
economizer is allowed to provide free cooling, the economizer
must determine exactly what set point it should try to maintain.
The set point the economizer attempts to maintain when “free
cooling” is located at Run Status
VIEWEC.C.P. This is
the economizer control point.
The control selects set points differently, based on the
control type of the unit. This control type can be found at
If the economizer is not allowed to do free cooling, then
EC.C.P = 0.
If the economizer is allowed to do free cooling and the
Unoccupied Free Cooling Mode is ON, then EC.C.P =
Setpoints
SASP + InputsRSETSA.S.R.
If the economizer is allowed to do free cooling and the
Dehumidification mode is ON, then EC.C.P = the Cooling
Control Point (Run Status
VIEWCL.C.P).
NOTE: To check the current cooling stage go to Run Status
CoolCUR.S.
If the C.TYP is either 1,2,3 or 4, and the unit is in a cool
mode, then EC.C.P = the Cooling Control Point (Run StatusVIEWCL.C.P).
Building Pressure Control — The N Series Com-
fortLink controller supports several physical rooftop configura-
tions which are used to control building pressure. This section
will describe the various types used. See Table 56.
SETTING UP THE SYSTEM — The building pressure configs are found at the local display under Configuration
Building Pressure Configuration (
tion selects the type of building pressure control in place
• BP.CF = 0, No building pressure control
• BP.CF = 1, VFD controlling power exhaust to modulate
building pressure control based on building pressure
sensor
• BP.CF = 2, VFD controlling return fan (VFD fan track-
ing)
Building Pressure Sensor (
the reading of a building pressure sensor when enabled. This
sensor configuration is automatically enabled when BP.CF = 1
or 2.
Building Pressure (+/-) Range (
establishes the range in H2O that a 4 to 20 mA sensor will be
scaled to. This configuration only allows sensors that measure
both "positive and negative" pressure.
Building Pressure Setpoint (
building pressure control setpoint. If configured for a type of
modulating building pressure control then this is the set point
that the control will try to clamp or control to.
Building Pressure Setpoint Offset (
pressure configurations BP.CF=1, this is the offset below the
building pressure set point that the building pressure must fall
below to turn off and disable power exhaust control.
VFD/ Actuator Fire Speed/Pos. (
and 2, this configuration is the fire speed override position
when the control is in the purge and evacuation smoke control
modes.
VFD/ Actuator Minimum Speed/Pos. (
BP.CF = 1 and 2, this configuration is the minimum VFD
speed/actuator position during building pressure operation below which the VFD/actuator may not control.
VFD Maximum Speed/Pos. (BP.MX) — For BP.CF = 1 and
2, this configuration is the maximum VFD speed during building pressure operation above which the VFD may not control.
Fan Track Learn Enable (
turn/exhaust control configuration selects whether the "fan
tracking" algorithm will make corrections over time and add a
"learned" offset to FT.ST. If this configuration is set to NO, the
unit will try to control the delta cfm value between the suppy
and return VFDs only based on FT.ST.
Fan Track Learn Rate (
turn/exhaust control configuration is a timer whereby corrections to the delta cfm operation are made. The smaller this value, the more often corrections may be made based on building
pressure error. This configuration is only valid when FT.CF =
Ye s .
Fan Track Initial DCFM (
turn/exhaust control configuration is the start point upon which
corrections (offset) is made over time when FT.CF = Yes and
is the constant control point for delta cfm control when FT.CF
= No.
Fan Track Max Clamp (
turn/exhaust control configuration is the maximum positive
delta cfm control value allowed unless outdoor air cfm control
is available and then the delta cfm control value would be
clamped to the outdoor air cfm value directly (see the Economizer section for a description of outdoor air cfm configuration).
Fan Track Max Correction (
return/exhaust control configuration is the max correction that
is possible to be made every time a correction is made based on
FT.TM. This configuration is only valid when FT.CF = Yes.
Fan Track Internal EEPROM (
this return/exhaust control internal EEPROM value is a learned
correction that is stored in non-volatile RAM and adds to the
offset when FT.CF = Yes. This value is stored once a day after
the first correction. This configuration is only valid when
FT.CF = Yes.
Fan Track Internal RAM (
return/exhaust control internal value is not a configuration but a
run time correction that adds to the offset when FT.CF = Yes
Building Pressure Setp.–0.25 - 0.25H20BPSP0.05
throughout the day. This value is only valid when FT.CF =
Ye s .
FT.CF) — For BP.CF = 2, this re-
Fan Track Reset Internal (
time reset of the internal RAM and internal EEPROM stored
FT.RS) — This option is a one
offsets. If the system is not set up right and the offsets are incorrect, this "learned" value can be reset.
Supply Air CFM Configuration (
SCF.C) — This configuration is set at the factory depending on whether a high or low
supply fan is installed. This information is then used by the
FT.TM) — For BP.CF = 2, this re-
control to determine the correct cfm tables to be used when
measuring supply air cfm.
Return/Exhaust Air CFM Configuration (
configuration is set at the factory depending on whether a high
or low return fan is installed. This information is then used by
the control to determine the correct cfm tables to be used when
FT.ST) — For BP.CF = 2, this re-
measuring return or exhaust air cfm.
Supply Air CFM Sensor (
SCF.S) — This configuration al-
lows the reading of supply air cfm when enabled.
FT.MX) — For BP.CF = 2, this re-
Return Air CFM Sensor (
lows the reading of return air cfm when enabled. This sensor
and ECF.S share the same analog input so are mutually exclu-
RCF.S) — This configuration al-
sive.
Exhaust Air CFM Sensor (
ECF.S) — This configuration allows the reading of exhaust air cfm when enabled. This sensor
and RCF.S share the same analog input so are mutually exclu-
sive.
FT.AD) — For BP.CF = 2, this
Building Pressure Run Rate (
2, this configuration is the PID run time rate.
Building Pressure Proportional Gain (
BP.TM) — For BP.CF = 1 and
BP.P) — For BP.CF =
1 and 2, this configuration is the PID Proportional Gain.
FT.OF) — For BP.CF = 2,
Building Pressure Integral Gain (
BP.I) — For BP.CF = 1 and
2, this configuration is the PID Integral Gain.
Building Pressure Derivative Gain (
BP.D) — For BP.CF = 1
and 2, this configuration is the PID Derivative Gain.
BUILDING PRESSURE CONTROL BASED ON BP.CF
FT.RM) — For BP.CF = 5, this
VFD Controlling Exhaust Fan Motors (
controlling high capacity power exhaust consists of an exhaust
fan VFD (Outputs
exhaust relay (Outputs
FA NSE.VFD) enabled by one power
FA NSP. E . 1 ). If building pressure
BP.CF =1) — VFD
REF.C) — This
81
(Pressures
AIR.PBP) rises above the building pressure set
point (BP.SP) and the supply fan is on, then building pressure
control is initialized. Thereafter, if the supply fan relay goes off
or if the building pressure drops below the BP.SP minus the
building pressure set point offset (BP.SO) for 5 continuous
minutes, building pressure control will be stopped. The 5-minute timer will continue to re-initialize if the VFD is still commanded to a position > 0%. If the building pressure falls below
the set point, the VFD will close automatically. Any time building pressure control becomes active, the exhaust fan relay turns
on which energizes the exhaust fan VFD. Control is performed
with a PID loop where:
Error = BP - BP.SP
K = 1000 * BP.TM/60 (normalize the PID control for run rate)
P = K * BP.P * (error)
I = K * BP.I * (error) + "I" calculated last time through the PID
D = K * BP.D * (error - error computed last time through the
PID)
VFD output (clamped between BP.MN and BP.MX%) = P + I
+ D
If building pressure (BP) rises above the building pressure
set point (BP.SP) and the supply fan is on, building pressure
control is initialized. Thereafter if the supply fan relay goes off
or if the building pressure drops below the BP.SP minus the
building pressure set point offset (BP.SO) for 5 continuous
minutes, building pressure control will be stopped. The 5-minute timer will continue to reload if the VFD is still commanded
to a position > 0%. If the building pressure falls below the set
point, the VFD will close automatically. Any time building
pressure control becomes active, the exhaust fan relay turns on
which energizes the exhaust fan VFD.
Return/Exhaust Control (
BP.CF =2) — The fan tracking algorithm controls the return fan VFD and the exhaust fan relay.
Fan tracking is the method of control used on plenum return
fan option. The ComfortLink control uses a flow station to
measure both the flow of both the supply and the return fans.
The control will measure the airflow of both the supply fan and
the return fan. The speed of the return fan is controlled by
maintaining a delta cfm (usually with supply airflow being
greater of the two) between the two fans. The building pressure
is controlled by maintaining this delta cfm between the two
fans. The higher that supply airflow quantity increases above
the return airflow, the higher the building pressure will be.
Conversely, as the return airflow quantity increases above the
supply airflow, the lower the building pressure will be. Whenever there is a request for the supply fan (or there is the presence of the IGC feedback on gas heat units), the return fan is
started. The delta cfm is defined as S.CFM - R.CFM. The return fan VFD is controlled by a PID on the error of delta cfm
actual from delta cfm set point. If the error is positive the drive
will increase speed. If the error is negative the drive will decrease speed.
NOTE: These configurations are used only if Fan Tracking
Learning is enabled. When Fan Tracking Learning is enabled,
the control will adjust the delta cfm (FT.ST) between the sup-
ply and return fan if the building pressure deviates from the
Building Pressure Set Point (BP.SP). Periodically, at the rate
set by the Fan Track Learn Rate (FT.TM), the delta cfm is
adjusted upward or downward with a maximum adjustment at
a given instance to be no greater than Fan Track Max Correction (FT.AD). The delta cfm can not ever be adjusted greater
than or less than the Fan Track Initial Delta Cfm (FT.ST) than
by the Fan Track Max Clamp (FT.MX).
Smoke Control Modes — There are four smoke con-
trol modes that can be used to control smoke within areas serviced by the unit: Pressurization mode, Evacuation mode,
Smoke Purge mode, and Fire Shutdown. Evacuation, Pressurization and Smoke Purge modes require the controls expansion
board (CEM). The Fire Shutdown input is located on the main
base board (MBB) on terminals TB201-1 and 2. The unit may
also be equipped with a factory-installed return air smoke detector that is wired to TB201-1,2 and will shut the unit down if
a smoke condition is determined. Field-monitoring wiring can
be connected to terminal TB201-1 and 2 to monitor the smoke
detector. Inputs on the CEM board can be used to put the unit
in the Pressurization, Evacuation, and Smoke Purge modes.
These switches or inputs are connected to TB202: Pressurization — TB202-18 and 19, Evacuation — TB202-16 and 17,
and Smoke Purge — TB202-14 and 15. Refer to Major System
Components section on page 127 for wiring diagrams.
Each mode must be energized individually on discrete inputs and the corresponding alarm is initiated when a mode is
activated. The fire system provides a normally closed dry
contact closure. Multiple smoke control inputs, sensed by the
control will force the unit into a Fire Shutdown mode.
FIRE SMOKE INPUTS — These discrete inputs can be
found on the local display under Inputs
and complete shutdown of the unit.
Pressurization Mode
— This mode attempts to raise the pressure of a space to prevent smoke infiltration from an adjacent
space. Opening the economizer (thereby closing the return air
damper), shutting down power exhaust and turning the indoor
fan on will increase pressure in the space.
Evacuation Mode
— This mode attempts to lower the pressure of the space to prevent infiltrating an adjacent space with
its smoke. Closing the economizer (thereby opening the returnair damper), turning on the power exhaust and shutting down
the indoor fan decrease pressure in the space.
Smoke Purge Mode
— This mode attempts to draw out
smoke from the space after the emergency condition. Opening
the economizer (thereby closing the return-air damper), turning
on both the power exhaust and indoor fan will evacuate smoke
and bring in fresh air.
AIRFLOW CONTROL DURING THE FIRE/SMOKE
MODES — All non-smoke related control outputs will get
shut down in the fire/smoke modes. Those related to airflow
will be controlled as explained below. The following matrix
specifies all actions the control shall undertake when each
mode occurs (outputs are forced internally with CCN priority
number 1 - “Fire”):
DEVICEPRESSURIZATION PURGE EVACUATION FIRE SD
Economizer100%100%0%0%
Indoor Fan —
VFD
Power Exhaust
VFD
Heat Interlock
Relay
*“FSO” refers to the supply and exhaust VFD fire speed override
configurable speed.
ON/FSO*ON/FSO*OFFOFF
OFFON/FSO*ON/FSO*OFF
ONONOFFOFF
SMOKE CONTROL CONFIGURATION
The economizer’s commanded output can be found in
Outputs
ECONECN.C.
The configurable fire speed override for supply fan VFD is in
Configuration
SP
SP.FS.
The supply fan relay’s commanded output can be found in
Outputs
FA NSS.FAN.
The supply fan VFD’s commanded speed can be found in
Outputs
FA NSS.VFD.
82
The configurable fire speed override for exhaust VFD/actuator
is in Configuration
BP
B.V.ABP.FS.
The exhaust fan VFD’s commanded speed can be found in
Outputs
FA NSE.VFD.
Indoor Air Quality Control — The indoor air quality
(IAQ) function will admit fresh air into the space whenever
space air quality sensors detect high levels of CO
When a space or return air CO
unit control, the unit’s IAQ routine allows a demand-based
sensor is connected to the
2
control for ventilation air quantity, by providing a modulating
outside air damper position that is proportional to CO
The ventilation damper position is varied between a minimum
ventilation level (based on internal sources of contaminants
and CO
maximum design ventilation level (determined at maximum
levels other than from the effect of people) and the
2
populated status in the building). Demand controlled ventilation (DCV) is also available when the ComfortLink unit is connected to a CCN system using ComfortID™ terminal controls.
This function also provides alternative control methods for
controlling the amount of ventilation air being admitted,
including fixed outdoor air ventilation rates (measured as cfm),
external discrete sensor switch input and externally generated
proportional signal controls.
The IAQ function requires the installation of the factoryoption economizer system. The DCV sequences also require
the connection of accessory (or field-supplied) space or return
air CO
installed outdoor air cfm option. External control of the
sensors. Fixed cfm rate control requires the factory-
2
ventilation position requires supplemental devices, including a
4 to 20 mA signal, a 10,000 ohm potentiometer, or a discrete
switch input, depending on the method selected. Outside air
CO
levels may also be monitored directly and high CO
2
economizer restriction applied when an outdoor air CO2 sensor
is connected. (The outdoor CO2 sensor connection requires
installation of the controls expansion module [CEM].)
The ComfortLink controls have the capability of DCV using an IAQ sensor. The indoor air quality (IAQ) is measured
using a CO
sensor whose measurements are displayed in parts
2
per million (ppm). The IAQ sensor can be field-installed in the
return duct. There is also an accessory space IAQ sensor that
can be installed directly in the occupied space. The sensor must
provide a 4 to 20 mA output signal. The sensor connects to
TB201 terminals 7 and 8. Be sure to leave the 182-ohm resistor
in place on terminals 7 and 8.
OPERATION — The unit’s indoor air quality algorithm modulates the position of the economizer dampers between two
user configurations depending upon the relationship between
the IAQ and the outdoor air quality (OAQ). Both of these values can be read at the Inputs
AIR.Q submenu. The lower of
these two configurable positions is referred to as the IAQ Demand Vent Min Position (IAQ.M), while the higher is referred
to as Economizer Minimum Position (EC.MN). The IAQ.M
should be set to an economizer position that brings in enough
fresh air to remove contaminants and CO
es other than people. The EC.MN value should be set to an
2
economizer position that brings in enough fresh air to remove
contaminants and CO
ple. The EC.MN value is the design value for maximum occu-
generated by all sources including peo-
2
pancy.
The logic that is used to control the dampers in response to
IAQ conditions is shown in Fig. 17. The ComfortLink controls
will begin to open the damper from the IAQ.M position when
the IAQ level begins to exceed the OAQ level by a configurable amount, which is referred to as Differential Air Quality
Low Limit (DAQ.L).
If OAQ is not being measured, OAQ can be manually configured. It should be set at around 400 to 450 ppm or measured
with a handheld sensor during the commissioning of the unit.
.
2
level.
2
generated by sourc-
The OAQ reference level can be set using the OAQ Reference
Set Point (OAQ.U). When the differential between IAQ and
OAQ reaches the configurable Diff. Air Quality Hi Limit
(DAQ.H), then the economizer position will be EC.MN.
When the IAQ–OAQ differential is between DAQ.L and
DAQ.H, the control will modulate the damper between IAQ.M
and EC.MN as shown in Fig. 17. The relationship is a linear
relationship but other non-linear options can be used. The
damper position will never exceed the bounds specified by
IAQ.M and EC.MN during IAQ control.
If the building is occupied and the indoor fan is running and
the differential between IAQ and OAQ is less than DAQ.L, the
economizer will remain at IAQ.M. The economizer will not
close completely. The damper position will be 0 when the fan
is not running or the building is unoccupied. The damper position may exceed EC.MN in order to provide free cooling.
The ComfortLink controls are configured for air quality
sensors which provide 4 mA at 0 ppm and 20 mA at 2000 ppm.
If a sensor has a different range, these bounds must be
reconfigured. These pertinent configurations for ranging the air
quality sensors are IQ.R.L, IQ.R.H, OQ.R.L and OQ.R.H. The
bounds represent the PPM corresponding to 4 mA (low) and
20 mA (high) for IAQ and OAQ, respectively.
If OAQ exceeds the OAQ Lockout Value (OAQ.L), then the
economizer will remain at IAQ.M. This is used to limit the use
of outside air which outdoor air CO
OAQ.L limit. Normally a linear control of the damper vs. the
levels are above the
2
IAQ control signal can be used, but the control also supports
non-linear control. Different curves can be used based on the
Diff.IAQ Responsiveness Variable (IAQ.R). See Fig. 18.
SETTING UP THE SYSTEM — The IAQ configuration op-
2
tions are under the Local Display Mode Configuration
See Table 57.
IAQ Analog Sensor Config (
ConfigurationIAQ
IAQ.
AQ.CFIQ.A.C) — This is used to configure the type of
IAQ position control. It has the following options:
• IQ.A.C = 0 (No analog input). If there is no other mini-
mum position control, the economizer minimum position
will be Configuration
IAQDCV.CEC.MN and
there will be no IAQ control.
• IQ.A.C = 1 (IAQ analog input). An indoor air (space or
return air) CO
sensor is also installed, or OAQ is broadcast on the CCN,
sensor is installed. If an outdoor air CO
2
2
or if a default OAQ value is used, then the unit can per-
form IAQ control.
• IQ.A.C = 2 (IAQ analog input with minimum position
override) — If the differential between IAQ and OAQ
is above Configuration
IAQAQ.SPDAQ.H, the
economizer minimum position will be the IAQ override
position (Configuration
IAQAQ.SPIQ.O.P).
• IQ.A.C = 3 (4 to 20 mA minimum position) — With a 4
to 20 mA signal connected to TB201 terminal 7 and 8,
the economizer minimum position will be scaled linearly
from 0% (4 mA) to EC.MN (20 mA).
• IQ.A.C = 4 (10K potentiometer minimum position) — With
a 10K linear potentiometer connected to TB201 terminal 7
and 8, the economizer minimum position will be scaled lin-
early from 0% (0 ohms) to EC.MN (10,000 ohms).
IAQ Analog Fan Config (
ConfigurationIAQAQ.CF
IQ.A.F) — This configuration is used to configure the control
of the indoor fan. If this option is used then the IAQ sensor
must be in the space and not in the return duct. It has the following configurations:
• IQ.A.F = 0 (No Fan Start) — IAQ demand will never
override normal indoor fan operation during occupied or
unoccupied period and turn it on.
• IQ.A.F = 1 (Fan On If Occupied) — IAQ demand will
override normal indoor fan operation and turn it on (if
83
off) only during the occupied period (CV operation with
100
500
700
1000
INSIDE/OUTSIDE CO
2
DIFFERENTIAL
INSIDE CO
2
CONCENTRATION
AQ
DIFFERENTIAL
LOW (DAQ.L)
AQ
DIFFERENTIAL
HIGH (DAQ.H)
MINIMUM
IAQ
DAMPER
POSITION
ECONOMIZER
MINIMUM
DAMPER
POSITION
INCREASING VENTILATION
VENTILATION FOR PEOPLE
VENTILATION FOR SOURCES
Fig. 17 — IAQ Control
NOTE: Calculating the IAQ.M and EC.MN damper position based
on differential IAQ measurement.
Based on the configuration parameter IAQREACT, the reaction to
damper positioning based on differential air quality ppm can be
adjusted.
IAQREACT = 1 to 5 (more responsive)
IAQREACT = 0 (linear)
IAQREACT = –1 to –5 (less responsive)
Fig. 18 — IAQ Response Curve
automatic fan).
• IQ.A.F = 2 (Fan On Occupied/Unoccupied) — IAQ
demand will always override normal indoor fan operation
and turn it on (if off) during both the occupied and unoccupied period. For IQ.A.F = 1 or 2, the fan will be turned on as
described above when DAQ is above the DAQ Fan On Set
Point (Configuration
IAQAQ.SPD.F.ON). The fan
will be turned off when DAQ is below the DAQ Fan Off Set
Point (Configuration
IAQAQ.SPD.F.OF). The con-
trol can also be set up to respond to a discrete IAQ input.
The discrete input is connected to TB202 terminal 12 and
13.
IAQ Discrete Input Config (
IQ.I.C) — This configuration is used to set the type of IAQ
ConfigurationIAQAQ.CF
sensor. The following are the options:
• IQ.I.C = 0 (No Discrete Input) — This is used to indicate
that no discrete input will be used and the standard IAQ
sensor input will be used.
• IQ.I.C = 1 (IAQ Discrete Input) — This will indicate
that the IAQ level (high or low) will be indicated by
the discrete input. When the IAQ level is low, the
economizer minimum position will be ConfigurationIAQDCV.CIAQ.M.
• IQ.I.C = 2 (IAQ Discrete Input with Minimum Position
Override. This will indicate that the IAQ level (high or
low) will be indicated by the discrete input and the economizer minimum position will be the IAQ override position, IQ.P.O (when high). It is also necessary to configure
how the fan operates when using the IAQ discrete input.
IAQ Discrete Fan Config (
IQ.I.F) — This is used to configure the operation of the
ConfigurationIAQAQ.CF
fan during an IAQ demand condition. It has the following
configurations:
• IQ.I.F = 0 (No Fan Start) — IAQ demand will never
override normal indoor fan operation during occupied or
unoccupied period and turn it on.
• IQ.I.F = 1 (Fan On If Occupied) — IAQ demand will
override normal indoor fan operation and turn it on (if
off) only during the occupied period (CV operation with
automatic fan).
• IQ.I.F = 2 (Fan On Occupied/Unoccupied) — IAQ
demand will always override normal indoor fan operation and turn it on (if off) during both the occupied and
unoccupied period.
Economizer Min Position (
EC.MN) — This is the fully occupied minimum economizer
ConfigurationIAQDCV.C
position.
IAQ Demand Vent Min Pos. (
ConfigurationIAQ
DCV.CIAQ.M) — This configuration will be used to set the
minimum damper position in the occupied period when there is
no IAQ demand.
IAQ Econo Override Pos (
ConfigurationIAQAQ.SP
IQ.O.P) — This configuration is the position that the econo-
mizer goes to when override is in effect.
TOAQ 4-20 mA Sensor Config (
ConfigurationIAQ
AQ.CFOQ.A.C) — This is used to configure the type of
outdoor sensor that will be used for OAQ levels. It has the following configuration options:
• OQ.A.C = 0 (No Sensor) — No sensor will be used and
the internal software reference setting will be used.
• OQ.A.C = 1 (OAQ Sensor with DAQ) — An outdoor
CO
sensor will be used.
2
• OQ.A.C = 2 (4 to 20 mA Sensor without DAQ).
OAQ Lockout Value (
ConfigurationIAQAQ.SP
OAQ.L) — This is the maximum OAQ level above which de-
mand ventilation will be disabled.
Diff. Air Quality Lo Limit (
DAQ.L) — This is the differential CO
ConfigurationIAQAQ.SP
level at which IAQ
2
control of the dampers will be initiated.
Diff. Air Quality Hi Limit (
DAQ.H) — This is the differential CO
ConfigurationIAQAQ.SP
level at which IAQ
2
control of the dampers will be at maximum and the dampers
will be at the Configuration
DAQ ppm Fan On Set Point (
IAQAQ.SPD.F.ON) — This is the CO
the indoor fan will be turned on.
DAQ ppm Fan Off Set Point (
IQ.R.L) — This is the reference that will be used with a to
non-Carrier IAQ sensor that may have a different characteristic
curve. It represents the CO
IAQ High Reference (
IQ.R.H) — This is the reference that will be used with a
level at 4 mA.
2
ConfigurationIAQAQ.SR
non-Carrier IAQ sensor that may have a different characteristic
curve. It represents the CO
OAQ Low Reference (
OQ.R.L) — This is the reference that will be used with a
level at 4 mA.
2
ConfigurationIAQAQ.S.R
non-Carrier OAQ sensor that may have a different characteristic curve. It represents the CO
OAQ High Reference (
level at 4 mA.
2
ConfigurationIAQAQ.S.R
OQ.R.H) — This is the reference that will be used with a nonCarrier OAQ sensor that may have a different characteristic
curve. It represents the CO
Diff. IAQ Responsiveness (
IAQ.R) — This is the configuration that is used to select the
level at 4 mA.
2
ConfigurationIAQAQ.SP
IAQ response curves as shown in Fig. 18.
PRE-OCCUPANCY PURGE — The control has the option
for a pre-occupancy purge to refresh the air in the space prior to
occupancy.
This feature is enabled by setting Configuration
IAQ
IAQ.PIQ.PG to Yes.
The IAQ Purge will operate under the following conditions:
• IQ.PG is enabled
• the unit is in the unoccupied state
• Current Time is valid
• Next Occupied Time is valid
• time is within two hours of the next occupied period
• time is within the purge duration (Configuration
IAQIAQ.PIQ.P.T)
If all of the above conditions are met, the following logic is
used:
If OAT IQ.L.O and OAT OCSP and economizer is
available then purge will be enabled and the economizer will
be commanded to 100%.
Else, if OAT < IQ.L.O then the economizer will be posi-
tioned to the IAQ Purge LO Temp Min Pos (Configuration
IAQIAQ.PIQ.P.L)
If neither of the above are true then the dampers will be
positioned to the IAQ Purge HI Temp Min Pos (Configuration
IAQIAQ.PIQ.P.H)
If this mode is enabled the indoor fan and heat interlock
relay (VAV) will be energized.
IAQ Purge (
ConfigurationIAQIAQ.PIQ.PG) — This
is used to enable IAQ pre-occupancy purge.
IAQ Purge Duration (
ConfigurationIAQIAQ.P
IQ.P.T) — This is the maximum amount of time that a purge
can occur.
IAQ Purge Lo Temp Min Pos (
ConfigurationIAQ
IAQ.PIQ.P.L) — This is used to configure a low limit for
damper position to be used during the purge mode.
IAQ Purge Hi Temp Min Pos (
ConfigurationIAQ
IAQ.PIQ.P.H) — This is used to configure a maximum position for the dampers to be used during the purge cycle.
IAQ Purge OAT Lockout Temp (
ConfigurationIAQ
IAQ.PIQ.L.O) — Nighttime lockout temperature below
which the purge cycle will be disabled.
OPTIONAL AIRFLOW STATION — The ComfortLink
controls are capable of working with a factory-installed optional airflow station that measures the amount of outdoor air entering the economizer. This flow station is intended to measure
ventilation airflows and has a limitation as to the maximum
flow rate it can measure. The limits are 52,500 cfm for sizes
75-105 ton units. The limit is 60,000 cfm for 120-150 ton units.
All configurations for the outdoor airflow station can be
found in the Configuration
ECONCFM.C, sub-menu.
For this algorithm to function, the Outdoor Air Cfm Sensor
Configuration (OCF.S.) must be enabled.
There are three set point configurations:
O.C.MN — Econ OACFM DCV Min Flow
O.C.MX — Econ OACFM DCV Max Flow
O.C.DB — Econ OACFM MinPos Deadbd
85
When the outdoor air cfm sensor is enabled, the Economizer
Min.Position (Configuration
the IAQ Demand Vent Min.Pos (ConfigurationIAQ
DCV.CIAQ.M) will no longer be used. During vent periods,
the control will modulate the damper to maintain the outdoor
air intake quantity between O.C.MX and O.C.MN. The indoor
air quality algorithm will vary the cfm between these two
values depending on Configuration
and the ConfigurationIAQAQ.SPDAQ.H set points
and upon the relationship between the IAQ and the outdoor air
quality (OAQ).
The economizer’s OA CFM Minimum Position Deadband
(O.C.DB) is the deadband range around the outdoor cfm
control point at where the damper control will stop, indicating
the control point has been reached. See the Economizer section
for more information.
IAQDCV.CEC.MN) and
IAQAQ.SPDAQ.L
Humidification — The N Series ComfortLink controls
can control a field-supplied and installed humidifier device.
The ComfortLink controls provide two types of humidification
control: A discrete stage control (via a relay contact) and a proportional control type (communicating to a LEN actuator). The
discrete stage control is used to control a single-stage humidifier, (typically a spray pump). The proportional control type is
typically used to control a proportional steam valve serving a
steam grid humidifier.
The ComfortLink controls must be equipped with a controls
expansion module and an accessory space or return air relative
humidity sensor.
If a humidifier using a proportional steam valve is selected,
the Carrier actuator (Carrier Part No. HF23BJ050) must be
adapted to the humidifier manufacturer’s steam valve. Contact
Belimo Aircontrols for information on actuator linkage adapter
packages required to mount the actuator on the specific brand
and type of steam valve mounted by the humidifier
manufacturer.
The actuator address must be programmed into the Com-fortLink unit’s humidifier actuator serial number variables.
SETTING UP THE SYSTEM — These humidity configuration are located in the local displays under ConfigurationHUMD. See Table 58. Related points are shown in Table 59.
Humidifier Control Configuration (
fier control can be set to the following configurations:
• HM.CF = 0 — No humidity control.
• HM.CF = 1 — Discrete control based on space relative
humidity.
• HM.CF = 2 — Discrete control based on return air rela-
tive humidity.
• HM.CF = 3 — Analog control based on space relative
humidity.
• HM.CF = 4 — Analog control based on return air rela-
tive humidity.
Humidity Control Set Point (
trol set point has a range of 0 to 100%.
Humidifier PID Run Rate (
time rate.
Humidifier Proportional Gain (
is the PID Proportional Gain.
HM.TM) — This is the PID run
HM.CF) — The humidi-
HM.SP) — The humidity con-
HM.P) — This configuration
Humidifier Integral Gain (
PID Integral Gain.
Humidifier Derivative Gain (
the PID Derivative Gain.
OPERATION — For operation, PID control will be utilized.
The process will run at the rate defined by the Configuration
HUMDH.PIDHM.TM. The first part of humidity
control tests the humidity control configuration and will turn
on corresponding configurations to read space or return air relative humidity. If the supply fan has been ON for 30 seconds
and the space is occupied, then the humidification is started.
Actuator Control
loop where:
Error = HM.SP – humidity sensor value (SP.RH or RA.RH,
depending on configuration).
The PID terms are calculated as follows:
P = K * HM.P * error
I = K * HM.I * error + “I” last time through
D = K * HM.D * (error – error last time through)
Where K = HM.TM/60 to normalize the effect of changing the
run time rate
Relay Output Control
greater than the humidity set point then the humidity relay
(Outputs
when the humidity is 2% less than the humidity set point.
CONFIGURING THE HUMIDIFIER ACTUATOR —
Every actuator used in the N Series control system has its own
unique serial number. The rooftop control uses this serial
number to communicate with the actuator. The actuator serial
number is located on a two-part sticker affixed to the side of the
actuator housing. Remove one of the actuator’s serial number
labels and paste it onto the actuator serial number records label
located inside the left-hand access panel at the unit’s control
panel. Four individual numbers make up this serial number.
Program the serial number of the actuator in its Humidifier Actuator Configurations group, ACT.C (SN.1, SN.2, SN.3, SN.4).
NOTE: The serial numbers for all actuators can be found
inside the control doors of the unit as well as on the actuator
itself. If an actuator is replaced in the field, it is a good idea to
remove the additional peel-off serial number sticker on the
actuator and cover up the old one inside the control doors.
Control Angle Alarm
C.A.LM) — The humidifier actuator learns what its end stops
are through a calibration at the factory. Field-installed actuators
may be calibrated in the Service Test mode. When an actuator
learns its end stops through calibration, it determines its control
angle. The actuator will resolve this control angle and express
its operation in a percent (%) of this learned range.
angle during calibration, the actuator will be unable to control
humidity. For this reason, the humidifier actuator has a configurable control angle alarm low limit (C.A.LM). If the control
angle learned through calibration is less than C.A.LM, an alert
will occur and the actuator will not function.
NOTE: This configuration does not typically need adjustment.
It is configurable for the small number of jobs which may
require a custom solution or workaround.
If the humidifier actuator has not learned a sufficient control
— Control is performed with a generic PID
GEN.OHUM.R) is closed. The relay will open
HM.I) — This configuration is the
HM.D) — This configuration is
— If the humidity sensor reading is
(ConfigurationHUMDACTC
86
Table 58 — Humidity Configuration
ITEMEXPANSIONRANGEUNITSCCN POINTDEFAULT
HUMDHUMIDITY CONFIGURATION
HM.CFHumidifier Control Cfg.0 - 4HUMD_CFG0
HM.SPHumidifier Setpoint0 - 100%HUSP40
H.PIDHUMIDIFIER PID CONFIGS
HM.TMHumidifier PID Run Rate10 - 120secHUMDRATE30
HM.PHumidifier Prop. Gain0 - 5HUMID_PG1
HM.IHumidifier Integral Gain0 - 5HUMID_IG0.3
HM.DHumidifier Deriv. Gain0 - 5HUMID_DG0.3
ACT.CHUMIDIFIER ACTUATOR CFGS
SN.1Humd Serial Number 10 - 9999HUMD_SN10
SN.2Humd Serial Number 20 - 6HUMD_SN20
SN.3Humd Serial Number 30 - 9999HUMD_SN30
SN.4Humd Serial Number 40 - 254HUMD_SN40
C.A.LMHumd Ctrl Angle Lo Limit0-90HUMDCALM85
Table 59 — Related Humidity Points
ITEMEXPANSIONUNITSCCN POINTWRITE STATUS
ConfigUNITSENSSRH.SSpace Air RH SensorSPRHSENS
ConfigUNITSENSRRH.SReturn Air RH SensorRARHSENS
ConfigUNITSENSMRH.SMixed Air RH SensorMARHSENS
InputsREL.HRA.RHReturn Air Rel. Humidity%RARHforcible
InputsREL.HSP.RHSpace Relative Humidity%SPRHforcible
InputsREL.HMA.RHMixed Air Relative Humidity%MARHforcible
OutputsACTUHMD.PHumidifier Act.Curr.Pos.%HUMDRPOS
OutputsACTUHMD.CHumidifier Command Pos.%HUMDCPOS
OutputsGEN.OHUM.RHumidifier RelayHUMIDRLY
Dehumidification and Reheat — The Dehumidifi-
cation function will override comfort condition set points based
on dry bulb temperature and deliver cooler air to the space in
order to satisfy a humidity set point at the space or return air
humidity sensor. The Reheat function will energize a suitable
heating system concurrent with dehumidification sequence
should the dehumidification operation result in excessive cooling of the space condition.
The dehumidification sequence requires the installation of a
space or return air humidity sensor or a discrete switch input. A
CEM (option or accessory) is required to accommodate an RH
(relative humidity) sensor connection. Reheat is also possible
using a heat reclaim coil (field-supplied and installed) or a hot
gas reheat coil (special order, factory-installed). Reheat is not
possible with electric heat or gas heat.
Dehumidification and reheat control are allowed during
Cooling and Vent modes in the occupied period.
On constant volume units using thermostat inputs (C.TYP =
3), the discrete switch input must be used as the dehumidification control input. The commercial Thermidistat device is the
recommended accessory device.
SETTING UP THE SYSTEM — The settings for dehumidification can be found at the local display at Configura-
tion
IAQ DEHU.
Dehumidification Configuration (
fication configuration can be set for the following settings:
• D.SEL = 0 — No dehumidification and reheat.
• D.SEL = 1 — The control will perform both dehumidifi-
cation and reheat with modulating valve (hydronic).
• D.SEL = 2 — The control will perform dehumidification
and reheat with staged gas only.
• D.SEL = 3 — The control will perform both dehumidifi-
cation and reheat with third party heat via an alarm relay.
In the case of D.SEL=3, during dehumidification, the
alarm relay will close to convey the need for reheat. A
typical application might be to energize a 3-way valve to
perform hot gas reheat.
• D.SEL = 4 — The control will use the Humidi-MiZer
adaptive dehumidification system.
• D.SEL = 5 — The control will perform both dehumidifi-
cation and reheat with third party heat reclaim via the
heat reclaim output. The heat reclaim output (H.SEL)
must be configured before D.SEL.
D.SEL) — The dehumidi-
Dehumidification Sensor (
figured for the following settings:
• D.SEN = 1 — Initiated by return air relative humidity
sensor.
• D.SEN = 2 — Initiated by space relative humidity sensor.
• D.SEN = 3 — Initiated by discrete input.
Economizer Disable in Dehum Mode (
configuration determines economizer operation during Dehumidification mode.
• D.EC.D = YES — Economizer disabled during dehumidification (default).
• D.EC.D = NO — Economizer not disabled during dehumidification.
Vent Reheat Set Point Select (
determines how the vent reheat set point is selected.
• D.V.CF = 0 — Reheat follows an offset subtracted from
return air temperature (D.V.RA).
• D.V.CF = 1 — Reheat follows a dehumidification heat
set point (D.V.HT).
Vent Reheat RAT Offset (
only during the vent mode. The air will be reheated to returnair temperature less this offset.
Vent Reheat Set Point
ing the vent mode. The air will be reheated to this set point.
Dehumidify Cool Set Point (
midification cooling set point.
Dehumidity RH Set Point (
fication relative humidity trip point.
Heat Reclaim Configuration (
claim configuration.
• H.SEL = 0 (NONE) — Heat reclaim is not performed.
• H.SEL = 1 (RELAY) — The control will perform both
dehumidification and reheat with third party heat via a
heat reclaim relay on the SCB board. In the case of
D.SEL=5, during dehumidification, the heat reclaim
®
relay will close to convey the need for "re-heat" need. A
typical application might be to energize a 3-way valve to
perform hot gas reheat.
• H.SEL = 2 (MODULATING) — The control will perform both dehumidification and reheat with modulating
valve (hydronic).
D.SEN) — The sensor can be con-
D.EC.D) — This
D.V.CF) — This configuration
D.V.RA) — Set point offset used
(D.V.HT) — Set point used only dur-
D.C.SP) — This is the dehu-
D.RH.S) — This is the dehumidi-
H.SEL) — This is the heat re-
87
OPERATION — Dehumidification and reheat can only occur
if the unit is equipped with either staged gas or hydronic heat.
Dehumidification without reheat can be done on any unit but
Configuration
IAQDEHUD.SEL must be set to 2.
If the machine’s control type is a TSTAT type (Configura-
tion
UNITC.TYP=3) and the discrete input selection for
the sensor is not configured (D.SEN not equal to 3), dehumidification will be disabled.
If the machine’s control type is a TSTAT type (Configura-
tion
UNITC.TYP=3) and the economizer is able to pro-
vide cooling, a dehumidification mode may be called out, but
the control will not request mechanical cooling.
NOTE: Configuring Configuration
IAQDEHU
D.SEN to 1, 2 or 3 will enable the CEM board along with the
sensor selected for control.
NOTE: If Configuration
IAQDEHUD.SEL = 1 or 2,
then either staged gas or hot water valve control will be automatically enabled (Configuration
HEATHT.CF will be
set to either 3 or 4).
If a tempering, unoccupied or “mechanical cooling locked
out” HVAC mode is present, dehumidification will be disabled.
An HVAC: Off, Vent or Cool mode must be in effect to launch
either a Reheat or Dehumidification mode.
If an associated sensor responsible for dehumidification
fails, dehumidification will not be attempted (SPRH, RARH).
Initiating a Reheat or Dehumidification Mode
— To call out
a Reheat mode in the Vent or the Off HVAC mode, or to call
out a Dehumidification mode in a Cool HVAC mode, one of
the following conditions must be true:
• The space is occupied and the humidity is greater than
the relative humidity trip point (D.RH.S).
• The space is occupied and the discrete humidity input is
closed.
Dehumidification and Reheat Control
— If a dehumidification mode is initiated, the rooftop will attempt to lower
humidity as follows:
• Economizer Cooling — The economizer, if allowed to per-
form free cooling, will have its control point (
tusVIEWEC.C.P
DEHUD.C.SP
D.EC.D
is disabled, the economizer will always be dis-
) set to
. If
ConfigurationIAQ
ConfigurationIAQDEHU
Run Sta-
abled during dehumidification.
• Cooling — For all cooling control types: A High Cool
HVAC mode will be requested internally to the control to
maintain diagnostics, although the end user will see a
Dehumidification mode at the display. In addition, for
multi-stage cooling units the cooling control point will
be set to Configuration
IAQDEHUD.C.SP (no
SASP reset is applied).
• Reheat When Cooling Demand is Present — For reheat
control during dehumidification: If reheat follows an
offset subtracted from return-air temperature (Configu-
ration
IAQDEHUD.SEL = 2), then no heating
will be initiated and the alarm relay will be energized. If
Table 60 — Dehumidification Configuration
Configuration
figuration
IAQDEHUD.SEL = 1 and Con-
HEATHT.CF = staged gas or hot water
valve, then the selected heating control type will operate
in the low heat/modulating mode.
• The heating control point will be whatever the actual
cooling set point would have been (without any supply
air reset applied).
• Reheat During Vent Mode — If configured (Configura-
tion
IAQDEHUD.V.CF = 0), the heating control
point will be equal to RAT - D.V.RA. If configured (Con-
figuration
IAQDEHUD.V.CF=1), the heating
control point will be equal to the D.V.HT set point.
Ending Dehumidification and Reheat Control
— When ei-
ther the humidity sensor fall 5% below the set point (Configu-
ration
IAQDEHUD.RH.S) or the discrete input reads
“LOW”, the Humidimizer mode will end.
Humidi-MiZer® Adaptive Dehumidification
System —
option are capable of providing multiple modes of improved
dehumidification as a variation of the normal cooling cycle.
The design of the Humidi-MiZer system allows for two humidity control modes of operation of the rooftop unit, utilizing a
common subcooling/reheat dehumidification coil located
downstream of the standard evaporator coil. This allows the
rooftop unit to operate in both a Dehumidification (Subcooling) mode and a hot gas Reheat Mode for maximum system
flexibility. The Humidi-MiZer package is factory installed and
will operate whenever there is a dehumidification requirement
present. The Humidi-MiZer system is initiated based on input
from a factory-installed return air humidity sensor to the large
rooftop unit controller. Additionally, the unit controller may receive an input from a space humidity sensor, a discrete input
from a mechanical humidistat, or third-party controller. Dehumidification and reheat control are allowed during Cooling and
Vent modes in the occupied period.
SET UP THE SYSTEM — The settings for Humidi-MiZer
system can be found at the local display at Configura-
tion
IAQDEHU. See Table 60.
Dehumidification Configuration (
fication configuration for Humidi-MiZer option is D.SEL = 4
(DH – HUMDZR).
Dehumidification Sensor (
figured for the following settings:
• D.SEN = 1 — Initiated by return air relative humidity
sensor.
• D.SEN = 2— Initiated by space relative humidity sensor.
• D.SEN = 3 — Initiated by discrete input.
The default sensor is the return air relative humidity sensor
(D.SEN = 1). Units ordered with the Humidi-MiZer option
will have factory-installed return air relative humidity sensors.
Economizer Disable in Humidi-MiZer Mode (
When D.SEL = 4 (DH – HUMDZR), this configuration is automatically set to D.EC.D = YES (Economizer disabled during
dehumidification).
D.V.CF) — This configuration
determines how the vent reheat set point is selected. This set
point becomes the supply air set point when the Humidi-MiZer
function is initiated and the unit enters a Reheat Mode (relative
humidity above set point with no cooling demand).
D.V.CF = 0 — Reheat follows an offset subtracted from re-
turn air temperature (D.V.RA).
D.V.CF = 1 — Reheat follows a dehumidification heat set
point (D.V.HT).
Vent Reheat RAT Offset (
D.V.RA) — Set point offset used
only when the Humidi-MiZer function is initiated and the unit
enters a Reheat Mode. This occurs when the relative humidity
is above set point with no cooling demand. The air will be reheated to return-air temperature less this offset.
Vent Reheat Set Point (
D.V.HT) — Set point used only when
the Humidi-MiZer function is initiated and the unit enters a Reheat Mode. This occurs when the relative humidity is above set
point with no cooling demand. When D.V.CF = 0, the supply
air will be reheated to D.V.HT minus D.V.RA. When D.V.CF =
1, the supply air will be reheated to D.V.HT.
Dehumidify Cool Set Point (
D.C.SP) — This is the HumidiMiZer cooling set point used to determine the temperature the
air will be cooled to prior to it being reheated to the desired
supply-air temperature. This set point is used during the Humidi-MiZer dehumidification and reheat modes of operation.
HZ.RT) — This is the rate (seconds) at which corrections are made in the position of the
modulating valves (C.EXV and B.EXV) to maintain supply air
set point.
Humidi-MiZer Proportional Gain (
HZ.PG) — This is the
proportional gain used in calculating the required valve position change for supply air temperature control. It is essentially
the percentage of total reheat capacity adjustment that will be
made per degree Fahrenheit of supply air temperature error.
OPERATION
Mode Qualifications
— An HVAC: Off, Vent or Cool mode
must be in effect to launch a Humidi-MiZer mode.
Sensor Failure
— If an associated sensor responsible for controlling Humidi-MiZer fails, dehumidification will not be attempted (SPRH, RARH).
Initiating a Humidi-MiZer Reheat or Dehumidification
Mode — To call out a Reheat mode in the “Vent” or the “Off”
HVAC mode, or to call out a Dehumidification mode in a
“Cool” HVAC mode, one of the following must be true:
• The space is occupied and the humidity is greater than
the relative humidity trip point (D.RH.S).
• The space is occupied and the discrete humidity input is
closed.
Ending a Humidi-MiZer Reheat or Dehumidification Mode
— When either the humidity sensor falls 5% below the set
point (Configuration
DEHUD.RH.S) or the discrete input
reads “LOW”, the Humidi-MiZer mode will end.
Relevant Outputs
— The Humidi-MiZer 3-way valve (reheat
valve) commanded output can be found in Out-
puts
COOLRHV.
The Humidi-MiZer Condenser Modulating Valve (Con-
denser EXV) position output can be found in Outputs
COOLC.EXV. The condenser position will be provided
as percent open.
HUMIDI-MIZER MODES
Dehumidification Mode (Subcooling)
— This mode will be
engaged to satisfy part-load type conditions when there is a
space call for cooling and dehumidification. Although the temperature may have dropped and decreased the sensible load in
the space, the outdoor and/or space humidity levels may have
risen. A typical scenario might be when the outside air is 85 F
and 70 to 80% relative humidity (RH). Desired SHR for equipment in this scenario is typically from 0.4 to 0.7. The HumidiMiZer unit will initiate Dehumidification mode when the space
temperature and humidity are both above the temperature and
humidity set points, and attempt to meet both set point requirements. Once the humidity requirement is met, the unit can continue to operate in normal cooling mode to meet any remaining
sensible capacity load. Alternatively, if the sensible load is met
and humidity levels remain high the unit can switch to Hot Gas
Reheat mode to provide neutral, dehumidified air.
Reheat Mode
— This mode is used when dehumidification is
required without a need for cooling, such as when the outside
air is at a neutral temperature but high humidity exists. This situation requires the equipment to operate at a low SHR of 0.0 to
0.2. With no cooling requirement and a call for dehumidification, the N Series Humidi-MiZer adaptive dehumidification
system will cycle on enough compressors to meet the latent
load requirement, while simultaneously adjusting refrigerant
flow to the Humidi-MiZer coil to reheat the air to the desired
neutral air set point. The N Series Humid-MiZer system controls allow for the discharge air to be reheated to either the return air temperature minus a configurable offset or to a configurable Reheat set point (default 70 F). The hot gas reheat mode
will be initiated when only the humidity is above the humidity
set point, without a demand for cooling.
System Control
— The essential difference between the Dehumidification mode and the Reheat mode is in the supply air
set point. In Dehumidification mode, the supply air set point is
the temperature required to provide cooling to the space. This
temperature is whatever the cooling control point would have
been in a normal cooling mode. In Reheat mode, the supply air
set point will be either an offset subtracted from return air temperature (D.V.RA) or the Vent Reheat Set Point (D.V.HT). Both
values are configurable. For both Dehumidification mode and
Reheat mode, the unit compressor staging will decrease the
evaporator discharge temperature to the Dehumidify Cool Set
Point (D.C.SP COOL) in order to meet the latent load and reheat the air to the required cooling or reheat set point. There is a
thermistor array called Temperatures
AIR.TCCT connect-
ed to the RCB. This thermistor array serves as the evaporator
discharge temperature (EDT). See Fig. 19.
The N-Series Humid-MiZer
®
system uses refrigerant flow
modulation valves that provide accurate control of the leavingair temperature as the evaporator discharge temperature is decreased to meet the latent load. As the refrigerant leaves the
compressor, the modulating valves vary the amount of refrigerant that enters and/or bypasses the condenser coil. As the bypassed and hot refrigerant liquid, gas or two-phase mixture
passes through the Humidi-MiZer coil, it is exposed to the cold
supply airflow coming from the evaporator coil. The refrigerant is subcooled in this coil to a temperature approaching the
evaporator leaving air temperature. The liquid refrigerant then
enters an electronic expansion valve (EXV) where the refrigerant pressure is decreased. The refrigerant enters the EXV and
evaporator coil at a temperature lower than in standard cooling
operation. This lower temperature increases the latent capacity
of the evaporator. The refrigerant passes through the evaporator
and is turned into a superheated vapor. The air passing over the
evaporator coil will become colder than during normal operation. However, as this same air passes over the Humidi-MiZer
reheat coil, it will be warmed to meet the supply air set point
temperature requirement. See Fig. 20.
Temperature Compensated Start — This logic is
used when the unit is in the unoccupied state. The control will
calculate early Start Bias time based on Space Temperature
deviation from the occupied cooling and heating set points.
This will allow the control to start the unit so that the space is at
conditioned levels when the occupied period starts. This is
89
required for ASHRAE (American Society of Heating, Refrig-
Evaporator Discharge Temperature
In Subcool or Reheat Mode, compressor staging
and increased subcooling drives evaporato
r
discharge temperature down to meet higher latent
loads
A
irflo
w
EVAPORATOR
HUMIDI-MIZER ADAPTIVE
DEHUMIDIFICATION
SYSTEM COIL
Supply Air Temperature Control
Innovative algorithm to control supply air temperature
modulates flow bypass to meet desired supply air setpoint no overcooling or overheating of the space.
Subcooling Mode: Meet Cooling Mode Supply Air Setpoint
Reheat Mode: Meet Return Air Offset or Reheat Setpoint (configurab le)
CCT
SAT
D.C.SP COOL
RAT-D.V.RA or
D.V.HT
Fig. 19 — Humidi-MiZer® System Control
3
4
EXPANSION
INDOOR AIR
EVAPORATOR
5
5'
EVAPORATOR
REHEAT HX
EXPANSION
DEVICE
4'
3'
CHECK VALVE
3- WAY VALV E
3a'
2'
2a'
BYPASS
MODULATING
VALV E
CONDENSER
OUTDOOR AIR
CONDENSER
MODULATING
VALV E
1'
COMPRESSOR
1
2
CONDENSER
OUTDOOR AIR
COMPRESSOR
CIRCUIT B
CIRCUIT a
Fig. 20 — Humidi-MiZer System Diagram
erating, and Air-Conditioning Engineers) 90.1 compliance. A
space sensor is required for non-linkage applications.
SETTING UP THE SYSTEM — The settings for temperature compensated start can be found in the local display under
Configuration
ITEMEXPANSIONRANGE UNITS CCN POINT
TCS.CTemp.Cmp.Strt.Cool Factr 0 - 60minTCSTCOOLTCS.HTemp.Cmp.Strt.Heat Factr 0 - 60minTCSTHEAT
TCST-Cool Factor (
UNIT.
TCS.C) — This is the factor for the start
time bias equation for cooling.
TCST-Heat Factor (
TCS.H) — This is the factor for the start
time bias equation for heating.
NOTE: Temperature compensated start is disabled when these
factors are set to 0.
TEMPERATURE COMPENSATED START LOGIC — The
following conditions must be met for the algorithm to run:
• Unit is in unoccupied state.
• Next occupied time is valid.
• Current time of day is valid.
• Valid space temperature reading is available (sensor or
DAV-Linkage).
90
The algorithm will calculate a Start Bias time in minutes us-
ing the following equations:
If (space temperature > occupied cooling set point)
Start Bias Time = (space temperature – occupied cooling set
point)* TCS.C
If (space temperature < occupied heating set point)
Start Bias Time = (occupied heating set point – space
temperature)*TCS.H
When the Start Bias Time is greater than zero the algorithm
will subtract it from the next occupied time to calculate the new
start time. When the new start time is reached, the Temperature
Compensated Start mode is set (Operating ModesT. C. S T), the fan is started and the unit controlled as in an occupied state. Once set, Temperature Compensated mode will stay
on until the unit goes into the Occupied mode. The Start Bias
Time will be written into the CCN Linkage Equipment Table if
the unit is controlled in DAV mode. If the Unoccupied Economizer Free Cool mode is active (Operating Modes
“UNOCC FREE COOL”) when temperature compensated
start begins, the Unoccupied Free Cool mode will be stopped.
MODE
HVAC =
Carrier Comfort Network® (CCN) — It is possible
to configure the ComfortLink controls to participate as an element of the Carrier Comfort Network (CCN) system directly
from the local display. This section will deal with explaining
the various programmable options which are found under the
CCN sub-menu in the Configuration mode.
The major configurations for CCN programming are located in the local displays at Configuration
Table 61.
CCN Address (
dress the rooftop is assigned.
CCN Bus Number (
bus the rooftop is assigned.
CCN Baud Rate (
baud rate.
CCN Time/Date Broadcast (
is set to ON, the control will periodically send the time and date
out onto the CCN bus once a minute. If this device is on a CCN
network then it will be important to make sure that only one
device on the bus has this configuration set to ON. If more than
one time broadcaster is present, problems with the time will
occur.
NOTE: Only the time and date broadcaster can perform
daylight savings time adjustments. Even if the rooftop is stand
alone, the user may want to set this to ON to accomplish the
daylight/savings function.
CCN OAT Broadcast (
to ON, the control will periodically broadcast its outside-air
temperature at a rate of once every 30 minutes.
CCN OARH Broadcast (
set to ON, the control will periodically broadcast its outside air
relative humidity at a rate of once every 30 minutes.
CCN OAQ Broadcast (
to ON, the control will periodically broadcast its outside air
quality reading at a rate of once every 30 minutes.
Global Schedule Broadcast (
set to ON and the schedule number (SCH.N) is between 65 and
99, then the control will broadcast the internal time schedule
once every 2 minutes.
CCN Broadcast Acknowledger (
ration is set to ON, then when any broadcasting is done on the
bus, this device will respond to and acknowledge. Only one device per bus can be configured for this option.
Schedule Number (
what schedule the control may follow.
CCNA) — This configuration is the CCN ad-
CCNB) — This configuration is the CCN
BAUD) — This configuration is the CCN
TM.DT) — If this configuration
OAT.B) — If this configuration is set
ORH.B) — If this configuration is
OAQ.B) — If this configuration is set
G. S . B ) — If this configuration is
B.ACK) — If this configu-
SCH.N) — This configuration determines
IAQCCN. See
SCH.N = 0The control is always occupied.
SCH.N = 1The control follows its internal time sched-
SCH.N = 65-99The control is either set up to receive to a
Accept Global Holidays? (
casting the time on the bus, it is possible to accept the time yet
not accept the global holiday from the broadcast message.
Override Time Limit (
the user to decide how long an override occurs when it is initiated. The override may be configured from 1 to 4 hours. If the
time is set to 0, the override function will become disabled.
Timed Override Hours (
number of hours left in an override. It is possible to cancel an
override in progress by writing “0” to this variable, thereby
removing the override time left.
SPT Override Enabled? (
ent, then it is possible to override an unoccupied period by
pushing the override button on the T55 or T56 sensor. This
option allows the user to disable this function by setting this
configuration to NO.
T58 Override Enabled? (
device that allows cooling/heating set points to be adjusted,
space temperature to be written to the rooftop unit, and the ability to initiate a timed override. This option allows the user to
disable the override initiated from the T58 sensor by setting
this option to NO.
Global Schedule Override? (
to receive global schedules then it is also possible for the global
schedule broadcaster to call out an override condition as well.
This configuration allows the user to disable the global schedule broadcaster from overriding the control.
ules. The user may enter any number
between 1 and 64 but it will be overwritten
to “1” by the control as it only has one
internal schedule.
broadcasted time schedule set to this
number or the control is set up to broadcast
its internal time schedule (G. S . B ) to the
network and this is the global schedule
number it is broadcasting. If this is the case,
then the control still follows its internal time
schedules.
HOL.T) — If a device is broad-
O.T.L) — This configuration allows
OV.EX) — This displays the current
SPT.O) — If a space sensor is pres-
T58.O) — The T58 sensor is a CCN
GL.OV) — If the control is set
Alert Limit Configuration — The ALLM submenu is
used to configure the alert limit set points. A list is shown in
Table 62.
SPT Low Alert Limit/Occ (
ture is below the configurable occupied SPT Low Alert Limit
(SP.L.O), then Alert 300 will be generated and the unit will be
stopped. The alert will automatically reset.
SPT High Alert Limit/Occ (
ture is above the configurable occupied SPT High Alert Limit
(SP.H.O), then Alert 301 will be generated and the unit will be
stopped. The alert will automatically reset.
SPT Low Alert Limit/Unocc (
perature is below the configurable unoccupied SPT Low Alert
Limit (SP.L.U), then Alert 300 will be generated and the unit
will be stopped. The alert will automatically reset.
SPT High Alert Limit/Unocc (
perature is above the configurable unoccupied SPT High Alert
Limit (SP.H.U), then Alert 301 will be generated and the unit
will be stopped. The alert will automatically reset.
EDT Low Alert Limit/Occ (
ture is below the configurable occupied evaporator discharge
temperature (EDT) Low Alert Limit (SA.L.O), then Alert 302
will be generated and cooling operation will be stopped but
heating operation will continue. The alert will automatically
reset.
SP.L.O) — If the space tempera-
SP.H.O) — If the space tempera-
SP.L.U) — If the space tem-
SP.H.U) — If the space tem-
SA.L.O) — If the space tempera-
91
EDT High Alert Limit/Occ (
SA.H.O) — If the space temperature is above the configurable occupied EDT High Alert Limit
(SA.H.O), then Alert 303 will be generated and heating operation will be stopped but cooling operation will continue. The
alert will automatically reset.
EDT Low Alert Limit/Unocc (
SA.L.U) — If the space temperature is below the configurable unoccupied EDT Low Alert
Limit (SA.L.U), then Alert 302 will be generated and cooling
operation will be stopped but heating operation will continue.
The alert will automatically reset.
EDT High Alert Limit/Unocc (
SA.H.U) — If the space temperature is above the configurable unoccupied EDT High Alert
Limit (SA.H.U), then Alert 303 will be generated and heating
operation will be stopped but cooling operation will continue.
The alert will automatically reset.
RAT Low Alert Limit/Occ (
RA.L.O) — If the return-air temperature is below the configurable occupied RAT Low Alert
Limit (RA.L.O), then Alert 304 will be generated and internal
routines will be modified. Unit operation will continue but
VAV heating operation will be disabled. The alert will automatically reset.
RAT High Alert Limit/Occ (
RA.H.O) — If the return-air
temperature is above the configurable occupied RAT High
Alert Limit (RA.H.O), then Alert 305 will be generated and
operation will continue. The alert will automatically reset.
RAT Low Alert Limit/Unocc (
RA.L.U) — If the return-air
temperature is below the configurable unoccupied RAT Low
Table 61 — CCN Configuration
Alert Limit (RA.L.U), then Alert 304 will be generated. Unit
operation will continue but VAV heating operation will be disabled. The alert will automatically reset.
RAT High Alert Limit/Unocc (
RA.H.U) — If the return-air
temperature is above the configurable unoccupied RAT High
Alert Limit (RA.H.U), then Alert 305 will be generated. Operation will continue. The alert will automatically reset.
OAT Low Alert Limit (
OAT.L) — If the outside-air temperature measured by the OAT thermistor is below the configurable
OAT Low Alert Limit (OAT.L) then Alert T316 will be
generated.
OAT High Alert Limit (
OAT.H) — If the outside-air temperature measured by the OAT thermistor is above the configurable OAT High Alert Limit (OAT.H) then Alert T317 will be
generated.
RARH Low Alert Limit (
R.RH.L) — If the unit is config-
ured to use a return air relative humidity sensor (Configura-
tion
UNITSENSRRH.S), and the measured level is
below the configurable RH Low Alert Limit (R.RH.L), then
Alert 308 will occur. The unit will continue to run and the alert
will automatically reset.
RARH High Alert Limit (
R.RH.H) — If the unit is config-
ured to use a return air relative humidity sensor (Configura-
tion
UNITSENSRRH.S), and the measured level is
above the configurable RARH High Alert Limit (R.RH.H),
then Alert 309 will occur. The unit will continue to run and the
alert will automatically reset.
SP.L.OSPT lo alert limit/occ-10-245dFSPLO60
SP.H.OSPT hi alert limit/occ-10-245dFSPHO85
SP.L.USPT lo alert limit/unocc-10-245dFSPLU45
SP.H.USPT hi alert limit/unocc-10-245dFSPHU100
SA.L.OEDT lo alert limit/occ-40-245dFSALO40
SA.H.OEDT hi alert limit/occ-40-245dFSAHO100
SA.L.UEDT lo alert limit/unocc-40-245dFSALU40
SA.H.UEDT hi alert limit/unocc-40-245dFSAHU100
RA.L.ORAT lo alert limit/occ-40-245dFRALO60
RA.H.ORAT hi alert limit/occ-40-245dFRAHO90
RA.L.URAT lo aler t limit/unocc-40-245dFRALU40
RA.H.URAT hi alert limit/unocc-40-245dFRAHU100
OAT.LOAT lo alert limit-40-245dFOATL-40
OAT.HOAT hi alert limit-40-245dFOATH150
R.RH.LRARH low alert limit0-100%RRHL0
R.RH.HRARH high alert limit0-100%RRHH100
O.RH .LOARH low alert limit0-100%ORHL0
O.RH .HOARH high alert limit0-100%ORHH100
SP.LSP low alert limit0-5"H2OSPL0
SP.HSP high alert limit0-5"H2OSPH2
BP.LBP lo alert limit-0.25-0.25"H2OBPL-0.25
BP.HBP high alert limit-0.25-0.25"H2OBPH0.25
IAQ.HIAQ high alert limit0-5000IAQH1200
92
OARH Low Alert Limit (
O.RH.L) — If the unit is config-
ured to use an outdoor air relative humidity sensor (Configura-
tion
ECONORH.S) and the measured level is below the
configurable OARH Low Alert Limit (O.RH.L), then economizer operation will be disabled. The unit will continue to run
and the alert will automatically reset.
OARH High Alert Limit (
O.RH.H) — If the unit is config-
ured to use a return air relative humidity sensor (Configura-
tion
ECONORH.S) and the measured level is above the
configurable OARH High Alert Limit (O.RH.H), then economizer operation will be disabled. The unit will continue to run
and the alert will automatically reset.
Supply Duct Pressure Low Alert Limit (
SP.L) — If the unit
is a VAV unit with a supply duct pressure sensor and the measured supply duct static pressure is below the configurable SP
Low Alert Limit (DP.L), then Alert 310 will occur. The unit
will continue to run and the alert will automatically reset.
Supply Duct Pressure High Alert Limit (
SP.H) — If the unit
is a VAV unit with a supply duct pressure sensor and the measured supply duct static pressure is above the configurable SP
High Alert Limit (SP.H), then Alert 311 will occur. The unit
will continue to run and the alert will automatically reset.
Building Pressure Low Alert Limit (
BP.L) — If the unit is
configured to use modulating power exhaust then a building
static pressure limit can be configured using the BP Low Alert
Limit (BP.L). If the measured pressure is below the limit then
Alert 312 will occur.
Building Pressure High Alert Limit (
BP.H) — If the unit is
configured to use modulating power exhaust then a building
static pressure limit can be configured using the BP Hi Alert
Limit (BP.H). If the measured pressure is above the limit, then
Alert 313 will occur.
Indoor Air Quality High Alert Limit (
is configured to use a CO
sensor and the level is above the
2
IAQ.H) — If the unit
configurable IAQ High Alert Limit (IAQ.H) then the alert will
occur. The unit will continue to run and the alert will automatically reset.
Sensor Trim Configuration — The TRIM submenu
is used to calibrate the sensor trim settings. The trim settings
are used when the actual measured reading does not match the
sensor output. The sensor can be adjusted to match the actual
measured reading with the trim function. A list is shown in
Table 63.
IMPORTANT: Sensor trim must not be used to extend
unit operation past the allowable operating range.
Doing so may impair or negatively affect the Carrier
product warranty.
Air Temperature Leaving Supply Fan Sensor (
variable is used to adjust the supply fan temperature sensor
reading. The sensor reading can be adjusted ± 10° F to match
the actual measured temperature.
Return Air Temperature Sensor Trim (
able is used to adjust the return air temperature sensor reading.
The sensor reading can be adjusted ± 10° F to match the actual
measured temperature.
Outdoor Air Temperature Sensor Trim (
able is used to adjust the outdoor air temperature sensor reading. The sensor reading can be adjusted ± 10° F to match the
actual measured temperature.
Space Temperature Sensor Trim (
SPT.T) — This variable is
used to adjust the space temperature sensor reading. The sensor
reading can be adjusted ± 10° F to match the actual measured
temperature.
Limit Switch Trim (
L.SW.T) — This variable is used to adjust the limit switch temperature sensor reading. The sensor
reading can be adjusted ± 10° F to match the actual measured
temperature.
SAT.T) — This
RAT.T) — This vari-
OAT.T) — This vari-
Air Temperature Leaving Evaporator Trim (
CCT.T) —This
variable is used to adjust the leaving evaporator temperature
sensor reading. The sensor reading can be adjusted ± 10° F to
match the actual measured temperature.
A1 Discharge Temperature (
DTA.1) — This variable is used
to adjust the A1 compressor discharge temperature sensor reading. The sensor reading can be adjusted ± 10° F to match the
actual measured temperature.
NOTE: Due to the resolution of the control board analog input,
temperature readings less than 50 F will become increasingly
inaccurate as the temperature decreases.
Suction Pressure Circuit A Trim (
SP.A.T) — This variable is
used to adjust the suction pressure sensor reading for circuit A.
The sensor reading can be adjusted ± 50 psig to match the actual measured pressure.
Suction Pressure Circuit B Trim (
SP.B.T) — This variable is
used to adjust the suction pressure sensor reading for circuit B.
The sensor reading can be adjusted ± 50 psig to match the actual measured pressure.
Discharge Pressure Circuit A Trim (
DP.A.T) — This variable is used to adjust the discharge pressure sensor reading for
circuit A. The sensor reading can be adjusted ± 50 psig to
match the actual measured pressure.
Discharge Pressure Circuit B Trim (
DP.B.T) — This variable is used to adjust the discharge pressure sensor reading for
circuit B. The sensor reading can be adjusted ±50 psig to match
the actual measured pressure.
Liquid Pressure Circuit A Trim (
LP.A.T) — This variable is
used to adjust the liquid pressure sensor reading for circuit A.
The sensor reading can be adjusted ± 50 psig to match the actual measured pressure.
Liquid Pressure Circuit B Trim (
LP.B.T) — This variable is
used to adjust the liquid pressure sensor reading for circuit B.
The sensor reading can be adjusted ± 50 psig to match the actual measured pressure.
4 to 20 mA Inputs
— There are a number of 4 to 20 mA in-
puts which may be calibrated. These inputs are located in
Inputs
4-20. They are:
• SP.M.T — static pressure milliamp trim
• BP.M.T — building pressure milliamp trim
• OA.M.T — outside air cfm milliamp trim
• RA.M.T — return air cfm milliamp trim
• SA.M.T — supply air cfm milliamp trim
Discrete Switch Logic Configuration — The SW.LG
submenu is used to configure the normally open/normally closed
settings of switches and inputs. This is used when field-supplied
switches or input devices are used instead of Carrier devices. The
normally open or normally closed setting may be different on a
field-supplied device. These points are used to match the control
logic to the field-supplied device.
The defaults for this switch logic section will not normally
need changing. However, if a field-installed switch is used that is
different from the Carrier switch, these settings may need adjustment.
IMPORTANT: Many of the switch inputs to the control
can be configured to operate as normally open or normally closed.
Settings for switch logic are found at the local displays
under the Configuration
Table 64.
Filter Status Input — Clean (
put for clean filters is set for normally open. If a field-supplied
filter status switch is used that is normally closed for a clean filter, change this variable to closed.
PFT.L) — The filter status
input for clean filters is set for normally open. If a field-supplied filter status switch is used that is normally closed for a
clean filter, change this variable to closed.
IGC Feedback — Off (
IGC.L) — The input for IGC feedback is set for normally open for off. If a field-supplied IGC
feedback switch is used that is normally closed for feedback
off, change this variable to closed.
Remote Switch — Off (
RMI.L) — The remote switch is set
for normally open when off. If a field-supplied control switch
is used that is normally closed for an off signal, change this
variable to closed.
Enthaply Input — Low (
ENT.L) — The enthalpy input is set
for normally closed when low. If a field-supplied enthalpy
switch is used that is normally open when low, change this
variable to open.
Fan Status Switch — Off (
SFS.L) — The fan status switch
input is set for normally open for off. If a field-supplied fan
status switch is used that is normally closed, change this
variable to closed.
Demand Limit Switch 1 — Off (
DL1.L) — The demand
limit switch no. 1 input is set for normally open for off. If a
field-supplied demand limit switch is used that is normally
closed, change this variable to closed.
Demand Limit Switch 2 — Off (
DL2.L) — The demand
limit switch no. 2 input is set for normally open for off. If a
field-supplied demand limit switch is used that is normally
closed, change this variable to closed.
IAQ Discrete Input — Low (
IAQ.L) — The IAQ discrete input is set for normally open when low. If a field-supplied IAQ
discrete input is used that is normally closed, change this variable to closed.
Fire Shutdown — Off (
FSD.L) — The fire shutdown input is
set for normally open when off. If a field-supplied fire
shutdown input is used that is normally closed, change this
variable to closed.
Pressurization Switch — Off (
PRS.L) — The pressurization
input is set for normally open when off. If a field-supplied pressurization input is used that is normally closed, change this
variable to closed.
Evacuation Switch — Off (
EVC.L) — The evacuation input
is set for normally open when off. If a field-supplied evacuation input is used that is normally closed, change this variable
to closed.
Smoke Purge — Off (
PRG.L) — The smoke purge input is
set for normally open when off. If a field-supplied smoke purge
input is used that is normally closed, change this variable to
closed.
Dehumidify Switch — Off (
DH.LG) — The dehumidify input is set for normally open when off. If a field-supplied
dehumidify input is used that is normally closed, change this
variable to closed.
SF Bypass Switch — Off (
SFB.L) — The Supply Fan bypass switch is normally open when off. It allows operation of
the supply fan through a bypass of the supply fan VFD.
PE Bypass Switch — Off (
PEB.L) — The Power Exhaust
bypass switch is normally open when off. It allows for operation of the exhaust fan through a bypass of the exhaust fan
VFD.
Display Configuration — The DISP submenu is used
to configure the local display settings. A list is shown in
Table 65.
Test Display LEDs (
tion of the ComfortLink display.
Metric Display (
the display from English units to Metric units.
Language Selection (
TEST) — This is used to test the opera-
METR) — This variable is used to change
LANG) — This variable is used to
change the language of the ComfortLink display. At this time,
only English is available.
94
Password Enable (
PAS.E) — This variable enables or disables the use of a password. The password is used to restrict
use of the control to change configurations.
Service Password (
PASS) — This variable is the 4-digit nu-
meric password that is required if enabled.
VFD Configurations — There are two sub-menus under
the Configuration menu, Configuration
Configuration
IAQE.VFD. These configurations are for
the supply fan or optional exhaust fan variable frequency
drives (VFDs). These sub-menus contain the configurations required for the Supply Fan and Exhaust Fan VFDs. This section
defines the configurations in these sub-menus. See Table 66
and 67. Further information on VFD configurations can be
found in Appendix D.
SUPPLY FAN VFD CONFIGURATION — The sub-menu
that contains these configurations is located at the local display
under Configuration
VFD1 Nominal Motor Volts (
IAQS.VFD.
N.VLT) — This configuration
defines the nominal motor voltage. This value must equal the
value on the motor rating plate. This value sets the maximum
drive output voltage supplied to the motor.
NOTE: The VFD cannot supply the motor with a greater voltage than the voltage supplied to the input of the VFD. Power to
the VFD must be cycled in order for a change to this configuration to take effect.
VFD1 Nominal Motor Amps (
N.AMP) — This configuration defines the nominal motor current. This value must equal
the value defined in the Supply Fan Motor Limitations
Table 21. Power to the VFD must be cycled in order for a
change to this configuration to take effect.
VFD1 Nominal Motor Freq (
N.FRQ) — This configuration
defines the nominal motor frequency. This value must equal
the value on the motor rating plate. This value sets the frequency at which the output voltage equals the Nominal Motor Volts
(N.VLT). Power to the VFD must be cycled in order for a
change to this configuration to take effect.
VFD1 Nominal Motor RPM (
N.RPM) — This configuration defines the nominal motor speed. This value must equal
the value on the motor rating plate. Power to the VFD must be
cycled in order for a change to this configuration to take effect.
IAQS.VFD and
Table 65 — Display Configuration
VFD1 Nominal Motor HPwr (
N.PWR) — This configuration defines the nominal motor power. This value must equal
the value on the motor rating plate. Power to the VFD must be
cycled in order for a change to this configuration to take effect.
VFD1 Motor Direction (
M.DIR) — This configuration sets
the direction of motor rotation. Motor direction change occurs
immediately upon a change to this configuration. Power to the
VFD need NOT be cycled for a change to this configuration to
take effect.
VFD1 Acceleration Time (
ACCL) — This configuration sets
the acceleration time from zero to maximum output frequency.
Power to the VFD must be cycled in order for a change to this
configuration to take effect.
VFD1 Deceleration Time (
DECL) — This configuration sets
the deceleration time from maximum output frequency to zero.
Power to the VFD must be cycled in order for a change to this
configuration to take effect.
VFD1 Switching Frequency (
SW.FQ) — This configuration
sets the switching frequency for the drive. Power to the VFD
must be cycled in order for a change to this configuration to
take effect.
EXHAUST FAN VFD CONFIGURATION — The submenu that contains these configurations is located at the local
display under Configuration
VFD2 Nominal Motor Volts (
IAQE.VFD.
N.VLT) — This configuration
defines the nominal motor voltage. This value must equal the
value on the motor rating plate. This value sets the maximum
drive output voltage supplied to the motor.
NOTE: The VFD cannot supply the motor with a greater voltage than the voltage supplied to the input of the VFD. Power to
the VFD must be cycled in order for a change to this configuration to take effect.
VFD2 Nominal Motor Amps (
N.AMP) — This configuration defines the nominal motor current. This value must equal
the value defined in:
• the High-Capacity Power Exhaust Systems Motor Limi-
tations table (Table 22) if BP.CF=4
• the Supply Fan Motor Limitations table (Table 21) if
BP.CF=5
• the Optional VFD Power Exhaust Motor Limitations
table (Table 68) if BP.CF=3
ITEMEXPANSIONRANGEUNITSCCN POINTDEFAULT
TESTTest Display LEDsON/OFFTESTOff
METRMetric DisplayON/OFFDISPUNITOff
LANGLanguage Selection0-1(multi-text strings)LANGUAGE0
PA S. EPassword EnableENABLE/DISABLEPASS_EBLEnable
PA SSService Password0000-9999PASSWORD1111
ITEMEXPANSIONRANGEUNITSCCN POINTDEFAULT
S.VFDSUPPLY FAN VFD CONFIG
N.VLTVFD1 Nominal Motor Volts0 to 999VoltsVFD1NVLT460*
N.AMPVFD1 Nominal Motor Amps0 to 999AmpsVFD1NAMP55.0*
N.FRQVFD1 Nominal Motor Freq10 to 500HzVFD1NFRQ60
N.RPMVFD1 Nominal Motor RPM50 to 30000RPMVFD1NRPM1750
N.PWRVFD1 Nominal Motor HPwr0 to 500 HPVFD1NPWR40*
M.DIRVFD1 Motor Direction0=FWD, 1=REV VFD1MDIR0
ACCLVFD1 Acceleration Time 0 to 1800secVFD1ACCL30
DECLVFD1 Deceleration Time0 to 1800secVFD1DECL30
SW.FQVFD1 Switching Frequency0=1kHz, 1=4kHz, 2=8kHz, 3=12kHzVFD1SWFQ2
*This default is model number dependent.
Table 66 — Supply Fan VFD Configuration
95
Table 67 — Exhaust Fan VFD Configuration
ITEMEXPANSIONRANGEUNITSCCN POINTDEFAULTS
E.VFDEXHAUST FAN VFD CONFIG
N.VLTVFD2 Nominal Motor Volts0 to 999VoltsVFD2NVLT460*
N.AMPVFD2 Nominal Motor Amps0 to 999AmpsVFD2NAMP28.7*
N.FRQVFD2 Nominal Motor Freq10 to 500HzVFD2NFRQ60
N.RPMVFD2 Nominal Motor RPM50 to 30000RPMVFD2NRPM1750
N.PWRVFD2 Nominal Motor HPwr0 to 500 H.P.VFD2NPWR20*
M.DIRVFD2 Motor Direction0=FWD, 1=REV VFD2MDIR0
ACCLVFD2 Acceleration Time 0 to 1800secVFD2ACCL30
DECLVFD2 Deceleration Time0 to 1800secVFD2DECL30
SW.FQVFD2 Switching Frequency0=1kHz, 1=4kHz, 2=8kHz, 3=12kHzVFD2SWFQ2
Power to the VFD must be cycled in order for a change to
this configuration to take effect.
VFD2 Nominal Motor Freq (
N.FRQ) — This configuration
defines the nominal motor frequency. This value must equal
the value on the motor rating plate. This value sets the
frequency at which the output voltage equals the Nominal Motor Volts (N.VLT). Power to the VFD must be cycled in order
for a change to this configuration to take effect.
VFD2 Nominal Motor RPM (
N.RPM) — This configuration defines the nominal motor speed. This value must equal
the value on the motor rating plate. Power to the VFD must be
cycled in order for a change to this configuration to take effect.
VFD2 Nominal Motor HPwr (
N.PWR) — This configuration defines the nominal motor power. This value must equal
the value on the motor rating plate. Power to the VFD must be
cycled in order for a change to this configuration to take effect.
VFD2 Motor Direction (
M.DIR) — This configuration sets
the direction of motor rotation. Motor direction change occurs
immediately upon a change to this configuration. Power to the
VFD need NOT be cycled for a change to this configuration to
take effect.
VFD2 Acceleration Time (
ACCL) — This configuration sets
the acceleration time from zero to maximum output frequency.
Power to the VFD must be cycled in order for a change to this
configuration to take effect.
VFD2 Deceleration Time (
DECL) — This configuration sets
the deceleration time from maximum output frequency to zero.
Power to the VFD must be cycled in order for a change to this
configuration to take effect.
VFD2 Switching Frequency (
SW.FQ) — This configuration
sets the switching frequency for the drive. Power to the VFD
must be cycled in order for a change to this configuration to
take effect.
VFD2 Type (
TYPE) — This configuration sets the type of
VFD communication. This configuration should not be
changed without first consulting a Carrier service engineering
representative.
Remote Control Switch Input — The remote switch
input is located on the RXB board and connected to TB201
terminals 3 and 4. The switch can be used for several remote
control functions. See Table 69.
Remote Input State
the actual real time state of the remote input.
Table 69 — Remote Switch Configuration
ITEMEXPANSIONRANGEUNITS
REMTRemote
RM.CFRemote Switch
RMI.LRemSw
Input State
Config
Off-Unoc-Strt-NoOv
Remote Switch Config
— This is the configuration that allows the user to assign different types of functionality to the remote discrete input.
• 0 — NO REMOTE SW — The remote switch will not be
used.
• 1 — OCC-UNOCC SW — The remote switch input will
control the occupancy state. When the remote switch
input is ON, the unit will forced into the occupied mode.
When the remote switch is OFF, the unit will be forced
into the unoccupied mode.
• 2 — STRT/STOP — The remote switch input will start
and stop the unit. When the unit is commanded to stop,
any timeguards in place on compressors will be honored
first. When the remote switch is ON, the unit will be
commanded to stop. When the remote switch is OFF the
unit will be enabled to operate.
• 3 — OVERRIDE SW — The remote switch can be used
to override any internal or external time schedule being
used by the control and force the unit into an occupied
mode when the remote input state is ON. When the
remote switch is ON, the unit will be forced into an occupied state. When the remote switch is OFF, the unit will
use its internal or external time schedules.
Remote Switch Logic Configuration
SW.LGRMI.L) — The control allows for the configuration
of a normally open/closed status of the remote input switch via
RMI.L. If this variable is configured OPEN, then when the
switch is open, the remote input switch perceives the logic state
as OFF. Correspondingly, if RMI.L is set to CLOSED, the remote input switch will perceive a closed switch as meaning
(InputsGEN.IREMT) — This is
ON/OFFRMTIN
0 - 3RMTINCFG
Open/CloseRMTINLOG
(ConfigurationUNIT RM.CF)
(Configuration
OFF. See Table 70.
CCN
POINT
96
Table 70 — Remote Switch Logic Configuration
REMOTE
SWITCH LOGIC
CONFIGURATION
(RMI.L)
OPEN
CLOSED
SWITCH
STATUS
OPENOFF (0)xxxxxUnoccupiedStartNo Override
CLOSEDON (1)xxxxxOccupiedStopOverride
OPENON (0)xxxxxOccupiedStopOverride
CLOSEDOFF (1)xxxxxUnoccupiedStartNo Override
REMOTE INPUT STATE
(REMT)
Hot Gas Bypass — The ComfortLink control system
supports the use of an optional minimum load hot gas bypass
valve (MLV) that is directly controlled by the ComfortLink
control system. This provides an additional stage of capacity as
well as low load coil freeze protection. Hot gas bypass is an
active part of the N-Series ComfortLink capacity staging and
minimum evaporator load protection functions. It is controlled
though the Minimum Load Valve function. The hot gas bypass
option consists of a solenoid valve with a fixed orifice sized to
provide a nominal 3-ton evaporator load bypass. A hot gas refrigerant line routes the bypassed hot gas from the discharge
line of circuit A to the suction line of circuit A. An additional
thermistor in the suction line allows the unit control to monitor
suction superheat. When the unit control calls for hot gas bypass, the hot gas bypasses the evaporator and adds refrigeration
load to the compressor circuit to reduce the cooling effect from
Circuit A.
The hot gas bypass system is a factory-installed option in-
stalled on Circuit A only. This function is enabled at Configu-
ration
COOLMLV. When this function is enabled, an ad-
ditional stage of cooling capacity is provided by the unit control staging sequences (see Appendix C).
Space Temperature Offset — Space Temperature Off-
set corresponds to a slider on a T56 sensor that allows the occupant to adjust the space temperature by a configured range
during an occupied period. This sensor is only applicable to
units that are configured as Multi-Stage SPT control (Configu-
ration
UNITC.TYP = 4).
ITEMEXPANSIONRANGE UNITS
SP.O.SSpace Temp
SP.O.RSpace Temp
SPTOSpace Temperature
Offset Sensor
Offset Range
Offset
Space Temperature Offset Sensor
SENSSP.O.S) — This configuration disables the reading
Enable/
Disable
1 - 10SPTO_RNG
+- SP. O . R ^FSPTO
(ConfigurationUNIT
CCN
POINT
SPTOSENS
of the offset slider.
Space Temperature Offset Range
UNITSENSSP.O.R) — This configuration establishes
(Configuration
the range, in degrees F, that the T56 slider can affect SPTO
when adjusting the slider from the far left (-SP.O.R) to the far
right (+SP.O.R). The default is 5° F.
Space Temperature Offset Value
SPTO) — The Space Temperature Offset Value is the read-
(TemperaturesAIR.T
ing of the slider potentiometer in the T56 that is resolved to
delta degrees based on SP.O.R.
TIME CLOCK CONFIGURATION
This section describes each Time Clock menu item. Not
every point will need to be configured for every unit. Refer to
the Controls Quick Start section for more information on what
set points need to be configured for different applications. The
REMOTE SWITCH CONFIGURATION (RM.CF)
0123
No Remote SwitchOcc-Unocc SwitchStart/StopOverride
Time Clock menu items are discussed in the same order that
they are displayed in the Time Clock table. The Time Clock
menu is shown in Table 71.
Hour and Minute (HH.MM) — The hour and minute
of the time clock are displayed in 24-hour, military time. Time
can be adjusted manually by the user.
When connected to the CCN, the unit can be configured to
transmit time over the network or receive time from a network
device. All devices on the CCN should use the same time. Only
one device on the CCN should broadcast time or problems will
occur.
Month of Year (MNTH) — This variable is the current
month of the calendar year.
Day of Month (DOM) — This variable is the current
day (1 to 31) of the month.
Day of Week (DAY) — This variable is the current day
of the week (Monday through Sunday).
Year (YEAR) — This variable is the current year (for ex-
ample, 2013).
Local Time Schedule (SCH.L) — This submenu is
used to program the time schedules. There are 8 periods
(PER.1 through PER.8). Each time period can be used to set
up a local schedule for the unit. Refer to the Programming
Operating Schedules section on page 29 for more information.
MONDAY IN PERIOD (PER.X
able is used to include or remove Monday from the schedule.
Each period is assigned an occupied on and off time. If this
variable is set to YES, then Monday will be included in that period’s occupied time schedule. If this variable is set to NO, then
the period’s occupied time schedule will not be used on Monday.
This variable can be set for Periods 1 through 8.
TUESDAY IN PERIOD (PER.X
able is used to include or remove Tuesday from the schedule.
Each period is assigned an occupied on and off time. If this
variable is set to YES, then Tuesday will be included in that period’s occupied time schedule. If this variable is set to NO, then
the period’s occupied time schedule will not be used on Tuesday. This variable can be set for Periods 1 through 8.
WEDNESDAY IN PERIOD (PER.X
This variable is used to include or remove Wednesday from the
schedule. Each period is assigned an occupied on and off time.
If this variable is set to YES, then Wednesday will be included
in that period’s occupied time schedule. If this variable is set to
NO, then the period’s occupied time schedule will not be used
on Wednesday. This variable can be set for Periods 1 through 8.
THURSDAY IN PERIOD (PER.X
variable is used to include or remove Thursday from the schedule. Each period is assigned an occupied on and off time. If this
variable is set to YES, then Thursday will be included in that
period’s occupied time schedule. If this variable is set to NO,
then the period’s occupied time schedule will not be used on
Thursday. This variable can be set for Periods 1 through 8.
DAYSMON) — This vari-
DAYSTUE) — This vari-
DAYSWED) —
DAYSTHU) — This
97
Table 71 — Time Clock Menu
ITEMEXPANSIONRANGECCN POINTDEFAULT
TIMETIME OF DAY
HH.MMHour and Minute00:00TIME
DATEMONTH,DATE,DAY AND YEAR
MNTHMonth of Yearmulti-text stringsMOY
DOMDay of Month0-31DOM
DAYDay of Weekmulti-text stringsDOWDISP
YEARYeare.g. 2003YOCDISP
SCH.LLOCAL TIME SCHEDULE
PER.1PERIOD 1
PER.1DAYSDAY FLAGS FOR PERIOD 1Period 1 only
PER.1DAYSMONMonday in PeriodYES/NOPER1MONYes
PER.1DAYSTUETuesday in PeriodYES/NOPER1TUEYes
PER.1DAYSWEDWednesday in PeriodYES/NOPER1WEDYes
PER.1DAYSTHUThursday in PeriodYES/NOPER1THUYes
PER.1DAYSFRIFriday in PeriodYES/NOPER1FRIYes
PER.1DAYSSATSaturday in PeriodYES/NOPER1SATYes
PER.1DAYSSUNSunday in PeriodYES/NOPER1SUNYes
PER.1DAYSHOLHoliday in PeriodYES/NOPER1HOLYes
PER.1OCCOccupied from00:00PER1_OCC00:00
PER.1UNCOccupied to00:00PER1_UNC24:00
Repeat for periods 2-8
HOL.LLOCAL HOLIDAY SCHEDULES
HD.01HOLIDAY SCHEDULE 01
HD.01MONHoliday Start Month0-12HOL_MON1
HD.01DAY Star t Day0-31HOL_DAY1
HD.01LEN Duration (Days)0-99HOL_LEN1
Repeat for holidays 2-30
able is used to include or remove Friday from the schedule.
Each period is assigned an occupied on and off time. If this
variable is set to YES, then Friday will be included in that period’s occupied time schedule. If this variable is set to NO, then
the period’s occupied time schedule will not be used on Friday.
This variable can be set for Periods 1 through 8.
SATURDAY IN PERIOD (PER.X
DAYSSAT) — This
variable is used to include or remove Saturday from the schedule. Each period is assigned an occupied on and off time. If this
variable is set to YES, then Saturday will be included in that
period’s occupied time schedule. If this variable is set to NO,
then the period’s occupied time schedule will not be used on
Saturday. This variable can be set for Periods 1 through 8.
SUNDAY IN PERIOD (PER.X
DAYSSUN) — This vari-
able is used to include or remove Sunday from the schedule.
Each period is assigned an occupied on and off time. If this
variable is set to YES, then Sunday will be included in that period’s occupied time schedule. If this variable is set to NO, then
the period’s occupied time schedule will not be used on Sunday. This variable can be set for Periods 1 through 8.
HOLIDAY IN PERIOD (PER.X
DAYSHOL) — This
variable is used to include or remove a Holiday from the schedule. Each period is assigned an occupied on and off time. If this
variable is set to YES, then holidays will be included in that period’s occupied time schedule. If this variable is set to NO, then
the period’s occupied time schedule will not be used on holidays. This variable can be set for Periods 1 through 8.
OCCUPIED FROM (PER.X
OCC) — This variable is used
to configure the start time of the Occupied period. All days in
the same period set to YES will enter into Occupied mode at
this time.
OCCUPIED TO (PER.X
UNC) — This variable is used to
configure the end time of the Occupied period. All days in the
same period set to YES will exit Occupied mode at this time.
Local Holiday Schedules (HOL.L) — This submenu
is used to program the local holiday schedules. Up to 30 holidays can be configured. When a holiday occurs, the unit will
follow the occupied schedules that have the HOLIDAY IN
PERIOD point set to YES.
Holiday Start Month (
HD.01 to HD.30MON) — This is
the start month for the holiday. The numbers 1 to 12 correspond to the months of the year (e.g., January = 1).
Holiday Start Day (
HD.01 to HD.30DAY) — This is the
start day of the month for the holiday. The day can be set from
1 to 31.
Holdiay Duration (
HD.01 to HD.30LEN) — This is the
length in days of the holiday. The holiday can last up to 99
days.
Daylight Savings Time (DAY.S) — The daylight sav-
ings time function is used in applications where daylight
savings time occurs. The function will automatically correct
the clock on the days configured for daylight savings time.
DAYLIGHT SAVINGS START (DS.ST) — This submenu
configures the start date and time for daylight savings.
Daylight Savings Start Month (
the start month for daylight savings time. The numbers 1 to 12
correspond to the months of the year (e.g., January = 1).
Daylight Savings Start Week (
the start week of the month for daylight savings. The week can
be set from 1 to 5.
Daylight Savings Start Day (
start day of the week for daylight savings. The day can be set
from 1 to 7 (Sunday=1, Monday=2, etc.).
Daylight Savings Minutes To Add (
is the amount of time that will be added to the time clock for
daylight savings.
DS.STST.MN) — This is
DS.STST.WK) — This is
DS.STST.DY) — This is the
DS.STMIN.A) — This
98
DAYLIGHT SAVINGS STOP (DS.SP) — This submenu configures the end date and time for daylight savings.
Daylight Savings Stop Month (
the stop month for daylight savings time. The numbers 1 to 12
correspond to the months of the year (e.g., January = 1).
Daylight Savings Stop Week (
the stop week of the month for daylight savings. The week can
be set from 1 to 5.
Daylight Savings Stop Day (
stop day of the week for daylight savings. The day can be set
from 1 to 7 (Sunday=1, Monday=2, etc.).
Daylight Savings Minutes To Subtract (
This is the amount of time that will be removed from the time
clock after daylight savings ends.
DS.SPSP.MN) — This is
DS.SPSP.WK) — This is
DS.SPSP.DY) — This is the
DS.SPMIN.S) —
TROUBLESHOOTING
The Navigator™ display shows the actual operating conditions of the unit while it is running. If there are alarms or there
have been alarms, they will be displayed in either the current
alarm list or the history alarm list. The Service Test mode allows operation of the compressors, fans, and other components
to be checked while the unit is not operating.
Complete Unit Stoppage — There are several condi-
tions that can cause the unit to not provide heating or cooling.
If an alarm is active which causes the unit to shut down, diagnose the problem using the information provided in the Alarms
and Alerts section on page 115, but also check for the following:
• Cooling and heating loads are satisfied.
• Programmed schedule.
• General power failure.
• Tripped control circuit transformers circuit breakers.
• Tripped compressor circuit breakers.
• Unit is turned off through the CCN network.
Single Circuit Stoppage — If a single circuit stops in-
correctly, there are several possible causes. The problem
should be investigated using information from the alarm and
alert list.
Service Analysis — Detailed service analysis can be
found in Tables 72-75 and Fig. 21.
Restart Procedure — Before attempting to restart the
machine, check the alarm list to determine the cause of the
shutdown. If a shutdown alarm for a particular circuit has occurred, determine and correct the cause before allowing the
unit to run under its own control again. When there is problem,
the unit should be diagnosed in Service Test mode. The alarms
must be reset before the circuit can operate in either Normal
mode or Service Test mode.
Humidi-MiZer® Troubleshooting — Use the unit
Navigator or a CCN device to view the status display and the
diagnostic display for information concerning cooling operation with the Humidi-MiZer system. Check the Current Alarms
and Alarm History for for any unresolved alarm codes and correct. Verify Humidi-MiZer configuration settings are correct
for the site requirements. If alarm conditions are corrected and
cleared, then operation of the compressors, fans, and HumidiMiZer valves may be verified by using the Service Test mode.
See page 29. In addition to the Cooling Service Analysis
(Table 72), see the Humidi-MiZer Service Analysis (Table 73)
for more information.
Thermistor Troubleshooting — Th e O AT, SAT,
RAT, CCT, T55, T56, and T58 temperature sensors use 10K
thermistors. Resistances at various temperatures are listed in
Table 76 and 77. The DTT, LT-A and LT-B use an 86K thermistor. See Table 78. The ST-A1, ST-A2, ST-B1, ST-B2 and
RGTA use a 5K thermistor. See Table 79 and 80.
THERMISTOR/TEMPERATURE SENSOR CHECK — A
high quality digital volt-ohmmeter is required to perform this
check.
1. With the unit powered down, remove the terminal strip of
the thermistor being diagnosed from the appropriate control board (MBB-J8 or RCB-J6). Connect the digital
ohmmeter across the appropriate thermistor terminals in
the terminal strip.
2. Using the resistance reading obtained, read the sensor
temperature from the appropriate sensor table.
3. To check thermistor accuracy, measure the temperature at
the thermistor location with an accurate thermocoupletype temperature measuring instrument. Insulate thermocouple to avoid ambient temperatures from influencing
reading. The temperature measured by the thermocouple
and the temperature determined from the thermistor resistance reading should be within 5° F (3° C) if care was taken in applying thermocouple and taking readings.
If a more accurate check is required, unit must be powered
down and thermistor removed and checked at a known temperature (freezing point or boiling point of water) by measuring
the resistance of the thermistor with the terminal strip removed
from the control board. With the terminal strip plugged back
into the control board and the unit powered up, compare the
temperature determined from the resistance measurement with
the value displayed by the control in the Temperatures menu
using the Navigator display.
99
Table 72 — Cooling Service Analysis
PROBLEM CAUSEREMEDY
Compressor and Fan Will Not
Start.
Compressor Cycles (Other Than
Normally Satisfying Thermostat).
Compressors Operates
Continuously.
Excessive Head Pressures.Loose condenser thermistors.Tighten thermistors.
Condenser Fans Not Operating.No Power to contactors.Fuse blown or plug at motor loose.
Excessive Suction Pressure.High heat load.Check for sources and eliminate
Suction Pressure Too Low.Dirty air filters.Replace air filters.
LEGEND
EXV — Expansion Valve Control Board
ST— Suction Temperature
Power failure.Check power source. Call power company.
Fuse blown or circuit breaker tripped. Check fuses
and circuit breakers in power and control panels.
Disconnect off.Power disconnect.
Compressor time guard to prevent short cycling.Check using ComfortLink Navigator display.
Thermostat or occupancy schedule set point not call-
ing for Cooling.
Outdoor temperature too low.Check Compressor Lockout Temperature (MC.LO)
Active alarm.Check active alarms using ComfortLink Navigator
Insufficient line voltage.Determine cause and correct.
Active alarm.Check active alarms using ComfortLink Navigator
Unit undersized for load.Decrease load or increase of size of unit.
Thermostat or occupancy schedule set point too low. Reset thermostat or schedule set point.
Dirty air filters.Replace filters.
Low refrigerant charge.Check pressure, locate leak, repair evacuate, and
Condenser coil dirty or restricted.Clean coil or remove restriction.
Dirty condenser coil.Clean coil.
Refrigerant overcharge.Recover excess refrigerant.
Faulty EXV.1. Check ST thermistor mounting and secure
EXV boad malfunction.Check alarm history for A169 (expansion valve con-
Condenser air restricted or air short cycling.Determine cause and correct.
Restriction in liquid tube.Remove restriction.
Faulty EXV.1. Check ST thermistor mounting and secure
EXV board malfunction.Check alarm history for A169 (expansion valve con-