McQuay UV15 Installation Manual
Operation Maintenance Manual OM 757-2
MicroTech II® Unit Ventilator Controls
for AAF®-HermanNelson® Classroom Unit Ventilators
Group: Applied Systems
Part Number: 106506330
Date: April 2010
2-Pipe Chilled Water Cooling Only-
Software Model UV15 (Valve Control)
Software Model UV16 (F&BP Damper Control)
Used with AAF-HermanNelson Classroom Unit Ventilator
Model AVS, AVV - Floor Mounted
Model AHF, AHV - Ceiling Mounted
IMPORTANT
Before unit commissioning, please read this publication in its entirety.
Develop a thorough understanding before starting the commissioning procedure.
This manual is to be used by the commissioner as a guide. Each installation is unique, only general topics are covered.
The order in which topics are covered may not be those required for the actual commissioning.
© 2010 McQuay International
Introduction 3
Acronyms/Abbreviations 5
Getting Started 7
Using the Keypad/Display 7
Display Format 7
Keypad Functions 7
Using the Keypad/Display 9
Menu Reference 9
Description of Operation 12
State Programming 12
UVC Unit Modes 13
OFF Mode (State 9) 14
Night Purge Mode (State 8) 15
Fan Only Mode (State A) 15
Emergency Heat Mode (Super State) 15
Auto Mode 16
Cool Mode (Super State) 18
“CO2 Demand Controlled Ventilation (optional)” on page 35Special
Purpose Unit Modes 22
Unit Mode Priority 24
Occupancy Modes 25
Occupied Mode 25
Unoccupied Mode 25
Standby Mode 25
Bypass Mode 26
Additional Occupancy Features 26
Networked Occupancy Sensor Capability 26
Unit-Mounted Time-Clock 26
Unit-Mounted Tenant Override Switch 26
Remote Wall-Mounted Sensor Tenant Override Switch 26
Remote Wall-Mounted Sensor Status LED 26
Space Temperature Set Points 27
Networked Set Point Capability 27
Networked Set Point Offset Capability 27
Networked Set Point Shift Capability 27
Networked Space Temperature Sensor Capability 27
Remote Wall-Mounted Sensor with +/–3°F
Adjustment (optional) 28
Remote Wall-Mounted Sensor with 55°F to 85°F
Adjustment (optional) 28
Effective Set Point Calculations 28
Proportional Integral (PI) Control Loops 30
Discharge Air Temperature Control 30
PI Control Parameters 31
Proportional Band 31
Integral Time 32
Indoor Air Fan Operation 32
Auto Mode 32
Occupied, Standby, and Bypass Operation 32
Unoccupied Operation 33
Cycle Fan 33
Off Delay 33
Outdoor Air Damper Operation 33
Minimum Position 33
Economizer Operation 33
Networked Space Humidity Sensor Capability 35
Networked Outdoor Humidity Sensor Capability 35
CO2 Demand Controlled Ventilation (optional) 35
Networked Space CO2 Sensor Capability 35
ASHRAE Cycle II 36
Valve Control (software model 15) 36
Face and Bypass Damper Control (software model 16) 36
End-of-Cycle Valve Control (software model 16) 36
Floating-Point Actuator Auto-Zero, Overdrive and Sync 36
Water Coil Leaving Air Thermostat (Freeze-stat) 37
Valve Control (software model 15) 37
Face & Bypass Damper Control (software model 16) 37
External Binary Inputs 37
External Binary Input 1 37
External Binary Input 2 38
External Binary Input 3 38
External Binary Outputs 39
External Binary Output 1 39
External Binary Output 2 39
External Binary Output 3 39
UVC Input and Output Table 41
Diagnostics and Service 42
Alarm and Fault Monitoring 42
Space Temp Sensor Failure () 42
Condensate Overflow Indication (optional) () 43
Outdoor Temp Sensor Failure () 43
Discharge Air Temp Sensor Failure () 43
Space Humidity Sensor Failure (optional) () 43
Outdoor Humidity Sensor Failure (optional) () 43
Space CO2 Sensor Failure (optional) () 44
Change Filter Indication () 44
EPROM Memory Indicator () 44
Configuration Display () 44
Troubleshooting Temperature Sensors 44
Troubleshooting Humidity Sensors 45
Troubleshooting Carbon Dioxide (CO2) Sensors 46
UVC Configuration Parameters 47
1 McQuay IM 708-2
Introduction
Introduction
This manual provides information on the MicroTech II® control system used in the AAF®-
®
HermanNelson
Unit Ventilator product line. It describes the MicroTech II components, input/
output configurations, field wiring options and requirements, and service procedures.
For installation and general information on the MicroTech II Unit Ventilator Controller, refer
to IM 747, MicroTech II Unit Ventilator Controller.
For installation, commissioning instructions, and general information on a particular unit
ventilator model, refer to the appropriate manual (Table 1), as well as accompanying software
operating instruction manual (T able 4), and possible accessory manuals that may pertain to the
unit (Table 3).
For installation and maintenance instructions on a plug-in communications card, refer to the
appropriate protocol-specific installation and maintenance manual (Table 2). For a description
of supported network variables for each protocol, refer to Protocol Data Packet bulletin ED
15065.
Copies of the latest version of these manuals are available for download on our website at
www. mcquay.com or from your local McQuay Representative.
Table 1: Model-spe c ific unit ventilator installation literature
Description Manual #
Vertical IM 817 X X X X
Horizontal IM 830 X X X X
Vertical Self-Contained IM 789 X X X X X X
AHF
AHB
AHV
AHR
AVS
AVB
AVV
AVR
AZB
AZR
AZS
AZU
AZV
AZQ
Table 2: Protocol-specific communication card installation literature and protocol data
Description Manual #
Unit Ventilator Unit Controller LonWorks® Communications Module IM 729
Unit Ventilator Unit Controller JCI N2 Open® Communications Module IM 730
Unit Ventilator Unit Controller BACnet® Communications Module IM 731
Protocol Data Packet ED-15065
Table 3: Accessory-specific installation literature
Description Manual #
MTII Unit Ventilator Controls Installation IM 747
Room Temperature Sensors Installation IM 629
ATS Service Cable Installation for Unit Ventilators IM 762
McQuay OM 757 3
Introduction
Table 4: Software program literature
Description Manual #
Air Source Heat Pump with Electric Heat (Software Model 00) OM 748
Water Source Heat Pump with Electric Heat (Software Model 02)
Water Source Heat Pump without Electric Heat (Software Model 03)
DX Cooling with Electric Heat (Software Model 04) OM 750
DX Cooling Only (Software Model 05) OM 751
Electric Heat Only (Software Model 06) OM 752
DX Cooling with Hydronic Heat - Valve Control (Software Model 07)
DX Cooling with Hydronic Heat - F&BP Damper Control (Software Model 08)
2-Pipe Hydronic Heat Only - Valve Control (Software Model 09)
2-Pipe Hydronic Heat Only - F&BP Damper Control (Software Model 10)
2-Pipe Chilled Water Cooling and Hot Water Heat - Valve Control (Software Model 11)
2-Pipe Chilled Water Cooling and Hot Water Heat - F&BP Damper Control (Software
Model 12)
4-Pipe Chilled Water Cooling and Hydronic Heat - Valve Control (Software Model 13)
4-Pipe Chilled Water Cooling and Hydronic Heat - F&BP Damper Control (Software
Model 14)
2-Pipe Chilled Water Cooling Only - Valve Control (Software Model 15)
2-Pipe Chilled Water Cooling Only - F&BP Damper Control (Software Model 16)
2-Pipe Chilled Water Cooling with Electric Heat - Valve Control (Software Model 17)
2-Pipe Chilled Water Cooling with Electric Heat - F&BP Damper Control (Software
Model 18)
OM 749
OM 753
OM 754
OM 755
OM 756
OM 757
OM 758
NOTICE
This equipment generates, uses, and can radiate radio frequency energy and, if not installed
and used in accordance with this instruction manual, may cause interference to radio
communications. It has been tested and found to comply with the limits for a Class A digital
device, pursuant to part 15 of the FCC rules. These limits are designed to provide
reasonable protection against detrimental interference when the equipment is operated in a
commercial environment. Operation of this equipment in a residential area is likely to cause
detrimental interference in which case users are required to correct the interference at their
own expense. McQuay International disclaims any liability resulting from any
interference or for the correction thereof.
WARNING
Electric shock hazard. Can cause personal injury or equipment damage.
This equipment must be properly grounded. Connections and service to the MicroTech II
control panel must be performed only by personnel that are knowledgeable in the operation
of the equipment being controlled.
CAUTION
Extreme temperature can damage system components.
The MicroTech II controller is designed to operate in ambient temperatures from -20°F to
125°F. It can be stored in ambient temperatures from -40°F to 140°F. It is designed to be
stored and operated in relative humidity up to 95% (non-condensing).
CAUTION
Static sensitive components. A static discharge while handling electronic circuit
boards can damage components.
Discharge any static electrical charge by touching the bare metal inside the main control
panel before performing any service work. Never unplug any cables, circuit board terminal
blocks, relay modules, or power plugs while power is applied to the panel.
4 McQuay OM 757
Introduction
Acronyms/Abbreviations
The following table list acronyms and abbreviations that may or may not be used within this
manual. Other abbreviations for keypad displays and parameters can be found in Table 7 on
page 10 and Table 26 on page 47.
Table 5: Acronyms and abbre v iations
Description
Air Fan AF
Auxiliary Heat End Differential AHED
Auxiliary Heat Start Differential AHSD
American Standard Code for Information Interchange ASCII
American Society of Heating, Refrigerating, and Air
Conditioning Engineers, Inc
Compressorized Cooling Lockout CCLO
Spac e CO
Chilled Water CW
Chilled Water Valve Position CWVP
Discharge Air DA
Discharge Air High Limit DAHL
Discharge Air Temperature DAT
Discharge Air Temperature Setpoint DATS
Demand Controlled Ventilation
DX Cooling Discharge Air Low Limit DXLL
Economizer Compare Differential ECD
Economizer IA/OA Enthalpy Differential EED
Economizer OA Enthalpy Setpoint EES
Emergency Heat Setpoint EHS
Exhaust Interlock OAD Min Position Setpoint EOAD
Outdoor Air Temperature Setpoint EOAT
End-of-Cycle EOC
EOC OAT Low Setpoint EOCS
Outdoor Air Humidity Output EORH
Space Humidity Setpoint ERH
Economizer IA/OA Temp Differential ETD
Economizer OA Temp Setpoint ETS
Source (water in) Temperature EWIT
Face and Bypass Damper Position FBDP
Federal Communications Commission FCC
Face and Bypass F & BP
Heating, Ventilating, Air Conditioning Refrigeration HVACR
Heating EOC Valve Setpoint HEOC
Hot Water HW
Indoor Air IA
Indoor Air Fan IAF
Indoor Air Temperature IAT
Light Emitting Diode LED
Local User Interface LUI
Mixed Air Low Limit MALL
Mechanical Cooling Low Limit Setpoint MCLL
National Electric Code NEC
Outside Air OA
Outside Air Dampers OAD
Energize Exhaust Fan OAD Setpoint OADE
OAD Min Position High-Speed Setpoint OADH
OAD Min Position Low-Speed Setpoint OADL
OAD Min Position Med-Speed Setpoint OADM
Outdoor Air Damper Position OADP
OAD Lockout Setpoint OALS
OAD Max Position Setpoint OAMX
Outside Air Temperature OAT
Setpoint CO2S
2
Acronym/
ASHRAE
DCV
Abr.
McQuay OM 757 5
Introduction
Description
Occupied Cooling Setpoint OCS
Occupied Heating Setpoint OHS
Occupancy Override Input OOI
Occupancy Sensor Input OSI
Proportional Integral PI
Parts Per Million PPM
Positive Temperature Coefficient PTC
Relative Humidity RH
Space Humidity Setpoint
Read Only RO
Read Write RW
Standby Cooling Setpoint SCS
Standby Heating Setpoint SHS
Thermal Expansion Valve TXV
Unoccupied Cooling Setpoint UCS
Unoccupied Heating Setpoint UHS
Unit Ventilator UV
Unit Ventilator Controller UVC
UVC (Heat/Cool) Mode Output UVCM
UVC State Output UVCS
Wet Heat Valve Position VALP
Ventilation Cooling Low Limit Setpoint VCLL
Ventilation Cooling Lockout VCLO
Ventilation Cooling Setpoint VCS
Wet Heat WH
Source (water in) Temperature Differential WITD
Acronym/
RHS
Abr.
6 McQuay OM 757
Getting Started
Getting Started
The MicroTech II U nit Vent Controller (UVC) is a self-contained device that is capable of
complete, stand-alone operation. Information in the controller can be displayed and modified
by using the keypad/display (local user interface). The following sections describe how to use
the keypad/display.
Note – Many UVC parameters are accessible both through the keypad/display and the network
interface. The shared keypad/display and the network interface variables have a “lastchange-wins” relationship.
Using the Keypad/Display
The keypad/display shown in Figure 1 is provided with all MicroTech II Applied Unit
Ventilator unit controllers. With the keypad/display, operating conditions, system alarms, and
control parameters can be monitored. Set points and other parameters also can be modified.
Figure 1: Keypad/display
MicroTechTMII
FAN ONLY
COOL
HEAT
AUTO
MODE FAN
HIGH
MED
LOW
AUTO
FUNC
ON /
STOP
Display Format
The keypad/display’s 2-digit, 7-segment display normally shows the effective heating or
cooling temperature set point (Effective Set Point Output). The display also is used to view
and modify UVC parameters as explained in the following sections.
Note – When the UVC is in the OFF mode, the effective heating set point appears in the display.
All other LEDs are switched off.
Keypad Functions
Security Levels
The keypad/display provides a 4-level password security feature that can be used to restrict
access. The available security levels are shown in Table 6.
Note – All unit ventilator controllers ship with the lowest security (level 0) enabled. To change
security levels, see Figure 2. Once a security level is changed, the keypad/display
remains at that security level until the next time it is changed.
Why can’t I use the MODE or FAN key or adjust Set Point Offset?
Most likely this is due to the security feature being used. If the security feature is set higher
than level 0, then some keypad/display functionality is locked out. To ensure this is not the
problem, enter the level 0 password then try to use the keypad/display again.
McQuay OM 757 7
Getting Started
Table 6: Keypad/display security levels
Level Display What is restricted? Password
0
1
2
3
Default level (access all) 10
Does not allow set point offset changes;
also locks out keypad/display menu
access.
Does not allow set point offset changes
nor MODE key changes; also locks out
keypad/display menu access.
Does not allow set point offset changes
nor MODE and FAN key changes; also
locks out keypad/display menu access.
21
32
43
Figure 2: Changing keypad/display security levels
ON/STOP Key and LED
Use the ON/STOP key to toggle the UVC between OFF mode and running (Application Mode
Input). The ON/STOP LED is off when the UVC is in the OFF mode.
Note – When the UVC is in the OFF mode, the effective heating set point appears in the display.
All other LEDs are switched off.
– The UVC archives each change to the keypad/display FAN and MODE keys. When the
ON/STOP key is used to bring the unit out of OFF mode, the UVC implements the last
active fan and unit modes.
– Each time the UVC power cycles, the UVC is in the auto fan and auto unit modes when
power is returned.
WARNING
Off mode is a “stop” state for the unit ventilator. It is not a “power
off” state. Power may still be provided to the unit.
FAN Key
Use the F AN key to toggle through each of the fan speeds (Fan Speed Command Input): Auto,
Low, Medium, and High.
MODE Key
Use the MODE key to toggle through the keypad/display accessible unit modes (Heat/Cool
Mode Input): Auto, Heat, Cool, and Fan Only.
Arrow Keys
Use the arrow keys to scroll between parameters and to adjust parameters.
FUNC Key
Use the Func key to view the actual space temperature or to confirm selection and changes to
user-adjustable parameters.
8 McQuay OM 757
Getting Started
Using the Keypad/Display
Viewing Actual Indoor Air Temperature (IAT)
Normally, the effective set point temperature appears on the keypad/display. You also can use
the keypad/display to view the indoor air temperature (IAT). See Figure 3.
Note – When the actual indoor air temperature (Effective Space Temp Output) equals the
effective set point temperature (Effective Set Point Output), you there is no change to the
keypad/display when you view space temperature.
Figure 3: Viewing indoor air temperature
70 71 70
Effective
set point
Changing Set Points
The keypad/display can be used to make a +/–5°F (+/–3°C) offset adjustment to the effective
temperature set point. See Figure 4. Also see “Space Temperature Set Points” on page 27 to
learn more about temperature set points.
Figure 4: Adjusting the set point offset
FUNC
Enter
(5-sec)
Actual space
temperature
Effective
set point
-1
Flash
value
FUNC
Enter
0
0
Current
offset
So 69
Effective
set point
70
Effective
set point
-1
Adjusted
offset
FUNC
Save
change
So
Set point
offset
Note – The set point offset clears whenever UVC power is cycled. When you change the set point
offset after a power cycle, or for the very first time, this cleared value shows as the highest
allowed value (5°F/3°C) but is not an actual offset value.
– When using the +/–3°F (+/–1.7°C) remote wall sensor, any set point offset adjustment
made at the keypad/display causes the UVC to override and ignore the remote wall
sensor set point adjustment knob. To use the remote wall sensor set point adjustment
knob after you changed the set point offset on the keypad/display, clear the keypad/
display set point offset by cycling UVC power.
– When using the 55°F to 85°F remote wall sensor, the UVC ignores any LUI set point offset
adjustments.
Menu Reference
The keypad/display menu eases troubleshooting and simplifies UVC configuration. The user
can access the most common parameters and system status values without a PC or network
interface.
The keypad/display menu is accessed via an unmarked, hidden key. This hidden key is located
approximately behind the letter “h” in the MicroTech II logo on the keypad/display face.
The keypad/display menu consists of two levels. The first level is the keypad/display Menu
Item List containing alphanumeric characters representing each parameter. The second level is
where the parameter’s value is viewed and adjusted if the parameter is adjustable. After 15seconds, an inactivity timer automatically causes the display to back out of the menu levels,
returning to the effective set point display.
McQuay OM 757 9
Getting Started
Figure 5: Changing a keypad/display menu item
Table 7: Keypad/display menu item list
Display Keypad menu item list Abr. Description
Reset Alarm Input
UVC (Heat/Cool) Mode
Output
UVC State Output UVCS
Discharge Air Temp Set
point Output
Discharge Air Temp Output DAT Display current DA temperature. RO x x
Ventilation Cooling Low
Limit set point
Mechanical Cooling Low
Limit set point
Slave Type Configuration
Valve Override Input
Effective Occupancy Output Display current occupancy. RO x x
Occupancy Override Input
Occupied Cooling set point OCS Adjust occupied cooling set point. RW x x
Standby Cooling Set point SCS Adjust standby cooling set point. RW x x
Unoccupied Cooling Set
point
Occupied Heating Set point OHS Adjust occupied heating set point. RW x x
Standby Heating Set point SHS Adjust standby heating set point. RW x x
Unoccupied Heating Set
point
Wall Sensor Type Set wall sensor type: 0 = +/–3F, 1 = 55°F to 85°F. RW x x 0
Outside Air Damper Position
Output
OAD Min Position High-
Speed Set point
OAD Min Position Med-
Speed Set point
OAD Min Position Low-
Speed Set point
Enter 1 to clear alarms (clears all inactive alarms, except filter alarm). To enable
the alarm again, enter 0.
Display current UVC mode. 1 = Heat, 3 = Cool, 4 = Night Purge, 6 = Off, 8 =
UVCM
Emerg. Heat, 9 = Fan Only
Display current UVC state. 1 = EconMech, 2 = Mech, 3 = Econ, 4 = DA Heat, 5
= Heat, 6 = ActiveDehum, 7 = Full Heat, 8 = Night Purge, 9 = Off, 10 = Fan Only,
11 = Heat Mode Cant Heat, 12 = CantCool, 13 = Emerg Heat Mode Cant Heat,
14 = Heat Mode Low Limit, 15 = Cool Mode Low Limit
DATS Display current DA temperature set point. RO x x
VCLL Adjust economizer cooling DA temperature low limit. RW x x
MCLL Adjust mechanical cooling DA temperature low limit. RW x x
Set slave type: 0 = Independent (slave uses own sensors), 1 = Dependent
(slave follows master). This feature requires a network over which the master
and slave UVCs can communicate.
Override valve position: 0 = normal operation, 36 = fully open all cooling valves,
37 = fully close all cooling valves. Adjusting this variable is intended only for
troubleshooting and hydronic system balancing. Once you are done, set this
variable to 0 or cycle unit power to return the UVC to normal operation.
Set occupancy: 0 = occupied, 1 = unoccupied, 2 = bypass, 3 = standby.
Adjusting this variable is intended only for troubleshooting. Once you are done,
cycle unit power to clear this variable and return the UVC to normal operation.
UCS Adjust unoccupied cooling set point. RW x x
UHS Adjust unoccupied heating set point. RW x x
OADP Display OA damper position. RO x x
Adjust OA damper minimum position with IAF at high speed. (This variable is
OADH
factory set to 5% open when the unit is ordered with optional
Adjust OA damper minimum position with IAF at medium speed. (This variable
OADM
is not used when the optional
OA damper minimum regardless of fan speed.)
Adjust OA damper minimum position with IAF at low speed. (This variable is not
OADL
used when the optional
damper minimum regardless of fan speed.)
CO2 DCV i s en abled . On ly OAD H is a cti ve as the
CO2 DCV is enabled. Only OADH is active as the OA
CO2 DCV.)
RO
15 16
1
RW
RW x x
RO x x
RO x x
RW x x 0
RW x x
RW x x
RW x x 20%
RW x x 25%
RW x x 30%
Default
54°F
(12°C)
45°F
(7°C)
73°F
(23°C)
77°F
(25°C)
82°F
(28°C)
70°F
(21°C)
66°F
(19°C)
61°F
(16°C)
2
2
10 McQuay OM 757
Display Keypad menu item list Abr. Description
Exhaust Interlock OAD Min
Position Set point
Energize Exhaust Fan OAD
Set point
OAD Max Position Set point OAMX Adjust OA damper maximum position. RW x x 99%
OAD Lockout Enable
OAD Lockout Set point OALS
Economizer Enable Set economizer status: 0 = disable, 1 = enable. RW x x 1
Economizer OA Temp Set
point
Economizer IA/OA Temp
Differential
Economizer OA Enthalpy
Set point
Economizer IA/OA Enthalpy
Differential
Space Humidity Output ERH Display room humidity (optional). 00 = No sensor connected. RO x x
Space Humidity Set point RHS Adjust room humidity set point for active dehumidification (optional). RW x 60%
Outdoor Air Humidity Output EORH Display OA humidity (optional). 00 = No sensor connected. RO x x
Outdoor Air Temp Output EOAT Display OA temperature. RO x x
Emergency Heat Enable Set emergency heat status: 0 = disable, 1 = enable. RW x x 1
Emergency Heat Set point EHS Adjust emergency heat set point. RW x x
Emergency Heat Shutdown
Configuration
Auxiliary Heat Start
Differential
Auxiliary Heat End
Differential
Auxiliary Heat Configuration Set auxiliary heat type: 0 = N.O. device, 1 = N.C. device. RW x 0
External BI-1 Configuration
External BI-3 Configuration
External BO-2 Configuration
External BO-3 Configuration
Fan Cycling Configuration
Filter Alarm Enable Set filter alarm status: 0 = disable, 1 = enable. RW x x 0
Reset Filter Alarm Input Enter 1 to clear filter alarm. RW x x
F&BP Damper Position
Output
CW Valve Position Output CWVP Display CW valve position. RO x x
Space Temp Sensor Offset Adjust this setting to bias the UVC measured space temperature. RW x x 0
Keypad/display
Temperature Units
1. RW = read and write capable, RO = read only.
2. If a menu value is greater than 2-digits (higher than 99), then
3. Additional UVC field configuration is required if the dewpoint/humidity binary input is used. Consult the factory.
Adjust OA damper position above which the exhaust fan output will be
EOAD
energized. There is a fixed –5% differential associated with this set point.
OADE Adjust OA damper minimum position when exhaust interlock input is energized. RW x x 12%
Set OA damper lockout feature status: 0 = disable, 1 = enable. (This variable is
factory set to 1 when the unit is ordered as a recirc unit with no OAD.)
Adjust OA temperature below which the OA damper closes if the OA damper
lockout is enabled. (This variable is factory set to –99°C when the unit is
ordered as a recirc unit with no OAD.)
Adjust economizer OA temperature set point. DO NOT lower this set point
ETS
below CCLO or you risk creating a deadband where no cooling occurs.
ETD Adjust economizer IA/OA temperature differential. RW x x
EES Adjust economizer OA enthalpy set point. RW x x
EED Adjust economizer IA/OA enthalpy differential. RW x x
Set emergency heat operation during shutdown, 0 = no emergency heat during
shutdown: 1 = allow emergency heat during shutdown.
AHSD Adjust auxiliary heat start differential. RW x
AHED Adjust auxiliary heat stop differential. RW x
Set the function of external binary input 1: 0 = unoccupied, 1 = dewpoint/
humidity switch
Set the function external binary Input 3: 0 = ventilation lockout, 1 = exhaust
interlock.
Set the function of external binary output 2: 0 = fault indication (default) or 1 =
pump restart output.
Set the function of external binary output 3: 0 = exhaust fan on/off signal, 1 =
auxiliary heat.
Set space fan cycles (switches off) during occupied, bypass, and standby
mode: 2 = continuous, 3 = cycling.
FBDP Display F&BP damper position. RO x
Set keypad/display temperature units in English or SI. This set point also effects
which unit types displayed over Metasys N2 and BACnet MS/TP networks
using the appropriate optional communications modules.
3
.
will be displayed on the keypad/display.
Getting Started
RO
15 16
1
RW
RW x x 99%
RW x x 0
RW x x
RW x x
RW x x 0
RW x 0
RW x x 0
RW x x 0
RW x 0
RW x x 2
Default
35.6°F
(2°C)
68°F
(20°C)
1.8°F
(1°C)
25 Btu/lb
(58 kJ/kg)
1.3 Btu/lb
(3 kJ/kg)
53.6°F
(12°C)
1.8°F
(1°C)
1.8°F
(1°C)
RW x x F
2
McQuay OM 757 11
Description of Operation
Description of Operation
State Programming
The MicroTech II UVC takes advantage of “state” machine programming to define and
control unit ventilator operation. “State” defines specific states or modes of operation for each
process within the unit ventilator (e.g., heating, cooling, etc.) and contain the specific logic for
each state. This eliminates some of the most common problems associated with control
sequences such as the possibility of simultaneous heating and cooling, rapid cycling, etc.
State machine programming, and the unique nature of state diagrams, can be easily used to
describe operation. It can simplify sequence verification during unit commissioning, as well as
simplify troubleshooting. With the unique combination of state machine programming and the
keypad/display’s ability to allow a technician to easily determine the active UVC state,
troubleshooting the UVC can be very simple.
The state diagrams presented in the following sections consist of several “elements” including
super states, states, conditional jumps (also called transitions) and transition points. Super
states are used as a means to group two or more related states into a single control function
such as cooling, or heating, etc. States are where all the actual work takes place, within each
state the UVC enables PI-loops and other logic sequences required to control unit ventilator
operation within that particular state, while other functions and PI-loops not needed durin g
that state may be disabled. Conditional jumps, or transitions, are the logic paths used by the
UVC to determine which state should be made active, these are the “questions” the UVC
continually considers. The transition point is simply a point through which a number of
conditional jumps meet. Think of it as a point where a number of questions must be
considered from which the UVC then determines which path is followed and which state is
then made active.
The UVC states and super states are used to define the “normal” unit modes, such as Off,
Night Purge, Fan Only, Emergency Heat, Auto, Cool, and Heat. The UVC also supports
several “special purpose” unit modes such as Purge, Pressurize, De-pressurize, and Shutdown,
which can be forced via a network connection and override typical UVC operation.
Note – Not all states or modes are available for all UV configurations, and some states (such as
Active Dehum) are optional.
– In the state descriptions below the terms, saturated high and saturated low, indicate that
the heating or cooling function being described has reached 100% or 0%, respectively.
12 McQuay OM 757
Figure 6: Complete UVC—state diagram
EmergencyHeat
ModeSuperState
FullHeat
CantHeat
Heat
LowLimit
7
D
5
E
FanOnly
A
NightPurge
8
Off
9
HeatMode
SuperState
AutoMode
Econ
EconMech
Mech
3
1
2
CantCool
C
DAHeat
LowLimit
4
F
CoolMode
SuperState
CantHeat
B
Description of Operation
UVC Unit Modes
The UVC provides several “normal” modes of unit operation. These include: Off, Night
Purge, Fan Only, Cool, Emergency Heat, Auto, Heat, and Cool.
Normal UVC modes can contain a single state or several states depending upon the
functionality required for each particular mode. Each UVC state is assigned a number, which
can be very helpful when trying to understand which state is currently active within the UVC.
To view the current UVC state number, use the keypad/display.
McQuay OM 757 13
Description of Operation
OFF
9
F
Table 8: UVC st a t e na mes and numbers
Normal UVC modes State names
OFF OFF 9 9 57
Night purge Night Purge 8 8 56
Fan only Fan Only 10 A 65
Emergency heat
Heat
Auto
Cool
Full Heat 7 7 55
Cant Heat 13 D 68
Heat 5 5 53
Cant Heat 11 B 66
Low Limit 14 E 69
EconMech 1 1 49
Mech 2 2 50
Econ 3 3 51
DA Heat 4 4 52
Cant Cool 12 C 67
Low Limit 15 F 70
Decimal ASCII Hex
State numbers
WARNING
Off mode is a “stop” state for the unit ventilator. It is not a “power
off” state. Power may still be provided to the unit.
OFF Mode (State 9)
Off mode is provided so that the UVC can be forced into a powered OFF condition. OFF mode
is a “stop” state for the unit ventilator; it is not a power off state. OFF mode consists of a
single UVC state: OFF [9].
When OFF mode becomes active, the UVC stops all normal heating, cooling, and ventilatio n
(OA damper is closed), and fan operation ends. The UVC continues to monitor space
conditions, indicate faults, and provide network communications (if connected to a network)
in the OFF mode while power is maintained to the unit.
While in OFF mode, the UVC does not maintain DA temperatures. If the space temperature
drops below EHS while in the OFF mode, the UVC is forced into the Emergency Heat mode
(see “Emergency Heat Mode (Super State)” on page 15).
Note – Special purpose unit modes such as Purge, Pressurize, and De-pressurize can force the
UVC to perform “special” functions during which the display appears to be in the OFF
mode.
Figure 7: Off state diagram
UVC Mode
UVC Mode OFF
OF
Transition
point
14 McQuay OM 757
Description of Operation
Night Purge
8
UVC Mode
Night purge
UVC Mode
Night purge
Transition
point
Fan Only
A
UVC Mode
Fan Only
UVC Mode
Fan Only
Transition
point
Night Purge Mode (State 8)
Night Purge mode is provided as a means to more easily and quickly ventilate a space. Night
purge can be useful in helping to remove odor build up at the end of each day, or after
cleaning, painting, or other odor generating operations occur within the space. Night Purge
mode consists of a single UVC state: Night Purge [8].
Night Purge is a full ventilation with exhaust mode, during which room comfort is likely to be
compromised. Therefore, McQuay strongly recommends using Night Purge only when the
space is unoccupied.
When Night Purge mode becomes active, the UVC stops all normal heating and cooling. Since
any new energy used to treat the incoming air would be wasted in the purge process. In the
Night Purge mode, the space fan is set to high speed, the OA damper is set to 100% open, and
the Exhaust Fan binary output (see “External Binary Outputs” on page 39) is set to ON. If the
UVC is not set to another mode within 1 hour (fixed), the UVC automatically switches to the
Fan Only mode (see “Fan Only Mode (State A)” on page 15).
While in Purge mode, the UVC does not maintain DA temperatures. If the space temperature
drops below the EHS, the UVC is forced into the Emergency Heat mode (see “Emergency
Heat Mode (Super State)” on page 15).
Figure 8: Night purge state diagram
Fan Only Mode (State A)
The Fan Only mode is provided so that the UVC can be forced into a Fan Only operation via a
keypad/display or a network connection. Fan Only mode consists of a single UVC state: Fan
Only [A].
When Fan Only mode becomes active, the UVC stops all normal heating and cooling.
While in Fan Only mode, the UVC does not maintain DA temperatures. If the space
temperature drops below the EHS, the UVC is forced into the Emergency Heat mode (see
“Emergency Heat Mode (Super State)”).
Figure 9: Fan only state diagram
Emergency Heat Mode (Super State)
The Emergency Heat mode is provided for situations where the UVC is in a mode that does
McQuay OM 757 15
not normally allow heating, such as OFF, Cool, Night Purge, or Fan Only. If Emergency Heat
mode is enabled, the UVC can automatically force itself into the Emergency Heat mode from
OFF, Cool, Night Pu rge, Fan Only, Purge, Pressurize, De-pressurize, and Shutdown.
Emergency Heat mode consists of UVC states: Full Heat [7] and Cant Heat [D].
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