Installing, starting up, and servicing this equipment can be
hazardous due to system pressures, electrical components, and
equipment location (roof, elevated structures, mechanical
rooms, etc.). Only trained, qualified installers and service
mechanics should install, start up, and service this equipment.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Catalog No. 04-53380003-01Printed in U.S.A.Form 38AP-1TPg 1210 11-09Replaces: New
When working on this equipment, observe precautions in
ENTER
ESCAPE
ENTER
the literature, and on tags, stickers, and labels attached to the
equipment, and any other safety precautions that apply. Follow
all safety codes. Wear safety glasses and work gloves. Use
care in handling, rigging, and setting this equipment, and in
handling all electrical components.
WARNING
Electrical shock can cause personal injury and death. Shut
off all power to this equipment during installation and
service. There may be more than one disconnect switch.
Tag all disconnect locations to alert others not to restore
power until work is completed.
WARNING
DO NOT VENT refrigerant relief valves within a building.
Outlet from relief valves must be vented outdoors in
accordance with the latest edition of ANSI/ASHRAE
(American National Standards Institute/American Society
of Heating, Refrigeration and Air Conditioning Engineers)
15 (Safety Code for Mechanical Refrigeration). The
accumulation of refrigerant in an enclosed space can
displace oxygen and cause asphyxiation. Provide adequate
ventilation in enclosed or low overhead areas. Inhalation of
high concentrations of vapor is harmful and may cause
heart irregularities, unconsciousness or death. Misuse can
be fatal. Vapor is heavier than air and reduces the amount
of oxygen available for breathing. Product causes eye and
skin irritation. Decomposition products are hazardous.
WARNING
DO NOT attempt to unbraze factory joints when servicing
this equipment. Compressor oil is flammable and there is
no way to detect how much oil may be in any of the
refrigerant lines. Cut lines with a tubing cutter as required
when performing service. 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 system. DO NOT re-use compressor oil.
CAUTION
This unit uses a microprocessor-based electronic control
system. Do not use jumpers or other tools to short out
components, 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.
CAUTION
Puron® refrigerant (R-410A) systems operate at higher
pressures than standard R-22 systems. Do not use R-22 service equipment or components on Puron refrigerant equipment. If service equipment is not rated for Puron
refrigerant, equipment damage or personal injury may
result.
CAUTION
GENERAL
This publication contains Controls Start-Up, Service,
Operation, and Troubleshooting information for the Gemini™
Select 38AP condensing units with ComfortLink controls. See
Table 1 for unit size information.
the ComfortLink™ electronic control system that controls and
monitors all operations of the unit.
The control system is composed of several components as
listed in the sections below. See Fig. 1-3 for typical control box
drawing. See Fig. 4-17 for power and control wiring.
The 38AP air-cooled condensing unit contains
Conventions Used in This Manual — The follow-
ing conventions for discussing configuration points for the
local display (scrolling marquee or Navigator™ accessory)
will be used in this manual.
Point names will be written with the mode name first, then
any sub-modes, then the point name, each separated by an
arrow symbol (. Names will also be shown in bold
and italics. As an example, the Lead/Lag Circuit Select Point,
which is located in the Configuration mode, Option sub-mode,
would be written as Configuration OPT2LLCS.
This path name will show the user how to navigate through
the local display to reach the desired configuration. The user
would scroll through the modes and sub-modes using the
and keys. The arrow symbol in the path name represents pressing 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,
ConfigurationOPT2LLCS= 2 (Circuit A leads).
Pressing the and keys simultaneously
will scroll an expanded text description of the point name or
value across the display. 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
referenced in the local display tables for users configuring the
unit with CCN software instead of the local display. The CCN
tables are located in Appendix B of the manual.
®
) point names are also
Refrigerant charge must be removed slowly to prevent loss
of compressor oil that could result in compressor failure.
2
Fig. 1 — Component Arrangement — Unit Sizes 025-030
LEGEND
AUX— Auxiliary
C—Contactor
CB— Circuit Breaker
CCHR— Crankcase Heater Relay
CSB— Current Sensor Board
EMM— Energy Management Module
EQUIP GND — Equipment Ground
FB— Fuse Block
FC— Fan Contactor
LON— Local Operating Network
MBB— Main Base Board
SW— Switch
TB— Terminal Block
TRAN— Transformer
UPC— Unitary Protocol Converter
3
Fig. 2 — Component Arrangement — Unit Sizes 040-060
LEGEND
AUX— Auxiliary
C—Contactor
CB— Circuit Breaker
CCH— Crankcase Heater Relay
CSB— Current Sensor Board
EMM— Energy Management Module
EQUIP GND — Equipment Ground
FC— Fan Contactor
FCB— Fan Circuit Breaker
LON— Local Operating Network
MBB— Main Base Board
MM— Motormaster
Fig. 3 — Component Arrangement — Unit Sizes 070-100
LEGEND
AUX— Auxiliary
C—Contactor
CB— Circuit Breaker
CCH— Crankcase Heater Relay
CSB— Current Sensor Board
CXB— Compressor Expansion Board
EMM— Energy Management Module
EQUIP GND — Equipment Ground
FC— Fan Contactor
FCB— Fan Circuit Breaker
LON— Local Operating Network
MBB— Main Base Board
SW— Switch
TB— Terminal Block
TRAN— Transformer
UPC— Unitary Protocol Converter
5
Fig. 4 — Power Wiring Schematic — 38APS,APD025-030
6
Fig. 5 — Power Wiring Schematic — 38APS040,050
7
8
Fig. 6 — Power Wiring Schematic — 38APD040-060
9
Fig. 7 — Power Wiring Schematic — 38APD070-100
10
Fig. 8 — Control Wiring Schematic — 38APS025-050
Fig. 9 — Control Wiring Schematic — 38APD025-060
11
12
Fig. 10 — Control Wiring Schematic — 38APD070-100
Legend and Notes for Fig. 4-10
LEGENDNOTES:
ACCSY— Accessory
ALM— Alarm
AMPS— Amperes
AUX— Auxiliary
C—Contactor
CB— Circuit Breaker
CCB— Compressor Circuit Breaker
CCH— Crankcase Heater Relay
CH— Crankcase Heater
COMP— Compressor
CSB— Current Sensor Board
CXB— Compressor Expansion Module
DGS— Digital Scroll
DPT— Discharge Pressure Transducer
DTT— Discharge Temperature Thermistor
DUS— Digital Unloaded Solenoid
EMM— Energy Management Module
EQUIP GND — Equipment Ground
FB— Fuse Block
FC— Fan Contactor
FCB— Fan Circuit Breaker
FIOP— Factory-Installed Option
FR— Fan Relay
FS— Fan Status
FU— Fuse
GND— Ground
HPS— High Pressure Switch
LLSV— Liquid Line Solenoid Valve
LV T— Low Voltage Terminal
MBB— Main Base Board
MLV— Minimum Load Valve
MM— Motormaster
MP— Modular Motor Protector
NEC— National Electrical Code
OAT— Outdoor Air Thermistor
OFM— Outdoor Fan Motor
OPT— Option
PL— Plug
RAT— Return Air Temperature
RGT— Return Gas Temperature
RLY—
SAT— Supply Air Temperature
SEN— Sensor Terminal Block
SET— Set Point Terminal Block
SPT— Suction Pressure Transducer
SW— Switch
TB— Terminal Block
TEMP— Temperature
TRAN— Transformer
UPC— Unitary Protocol Converter
Y—Cool Stage
Relay
1. Factory wiring is in accordance with UL (Underwriters Laboratories) 1995 standards. Any field modifications or additions
must be in compliance with all applicable codes.
2. Use 75 C minimum wire for field power supply.
3. All field interlock contacts must have a minimum rating of
2 amps at 24-vac sealed. See field interlock wiring.
4. Compressor and fan motors are thermally protected. Threephase motors protected against single-phase conditions.
5. Terminals 13 and 14 of LVT are for field connection of remote
on-off. The contact must be rated for dry circuit application
capable of handling a 5-vdc, 1 mA to 20 mA load.
6. For 500 series unit operation at 208-3-60 line voltage, TRAN1
primary connections must be moved to terminals H3 and H4.
7. For 575-3-60 units, fan circuit breakers FCB1 and FCB2 are
replaced with fuse blocks FB1 and FB2.
8. For units with low ambient Motormaster
option or field-installed acessory, fan contactors FC1 and FC2
are replaced with fan relays FR1 and FR2.
9. MP-A1 not used in the following units:
070-100: 400-v, 460-v units without digital scroll
10. MP-A2 not used in the following units:
070-100: 400-v, 460-v
11. MP-B1 not used in the following units:
070: all units
080-100: 400-v, 460-v
12. MP-B2 not used in the following units:
070: all units
080-100: 400-v, 460-v
13. MP-A3 not used in the following units:
090,100: 400-v, 460-v
14. MP-B3 not used in the following units:
070: all units
080-100: 400-v, 460-v
15. Jumper plug required when modular motor protector is not
used.
®
V factory-installed
13
OUTSIDE
AIR
DUCT
SUPPLY
RETURN
AIR
MAT/RATSATFS1*
FAN
EVAPORATOR
COIL
Fig. 11 — Field Power Wiring
LEGEND
NOTES:
1. Factory wiring is in accordance with UL 1995 standards. Field modifications
or additions must be in compliance with all applicable codes.
2. All units or modules have single point primary power connection. Main
power must be supplied from a field or factory-supplied disconnect.
3. Wiring for main field supply must be rated 75 C. Use copper conductors only.
a. Incoming wire size range for terminal block with MCA (minimum circuit
amps) up to 175 amps is 14 AWG (American Wire Gage) to 2/0.
b. Incoming wire size range for terminal block with MCA from 175.1 amps to
420 amps is 2 AWG to 600 kcmil.
c. Incoming wire size range for non-fused disconnect with MCA up to
100 amps is 14 AWG to 1/0.
d. Incoming wire size range for non-fused disconnect with MCA from
100.1 amp to 200 amps is 6 AWG to 350 kcmil.
e. Incoming wire size range for non-fused disconnect with MCA from
200.1 amp to 450 amps is 3/0 to 500 kcmil.
4. Refer to certified dimensional drawings for exact locations of the main power
and control power entrance locations.
EQUIP GND — Equipment Ground
NEC— National Electrical Code
a38-7122
LEGEND
*FS1 can be pressure differential switch (shown), motor current detection, or sail switch.
FS1— Fan Status Switch (24-v)
MAT — Mixed Air Temperature Sensor
RAT — Return Air Temperature Sensor
SAT — Supply Air Temperature Sensor
a38-7133
Fig. 12 — MAT/RAT and SAT Sensor Layout
14
a38-7125
a38-7127
*See Fig. 12 for MAT/RAT and SAT location.
†Not required for single circuit units.
Fig. 15 — Constant Volume Application Wiring Diagram Space Temperature Sensor Control, Sizes 025-100
*See Fig. 12 for MAT/RAT and SAT location.
†Not required for single circuit units.
Fig. 17 — Optional Energy Management Module Wiring
a38-7129
Legend and Notes for Fig. 13-17
LEGEND
NOTES:
1. Factory wiring is in accordance with UL 1995 standards. Field
modifications or additions must be in compliance with all applicable codes.
2. All units or modules have single point primary power connection. Main power must be supplied from a field or factorysupplied disconnect.
3. Wiring for main field supply must be rated 75 C. Use copper
conductors only.
a. Incoming wire size range for terminal block with MCA (mini-
mum circuit amps) up to 175 amps is 14 AWG (American
Wire Gage) to 2/0.
b. Incoming wire size range for terminal block with MCA from
175.1 amps to 420 amps is 2 AWG to 600 kcmil.
c. Incoming wire size range for non-fused disconnect with MCA
up to 100 amps is 14 AWG to 1/0.
d. Incoming wire size range for non-fused disconnect with MCA
from 100.1 amp to 200 amps is 6 AWG to 350 kcmil.
e. Incoming wire size range for non-fused disconnect with MCA
from 200.1 amp to 450 amps is 3/0 to 500 kcmil.
4. Terminals 1 and 2 of the LVT are for the alarm relay. The maximum load allowed for the alarm relay is 5-va sealed and 10-va
inrush at 24-v. Field power supply is not required.
5. Refer to certified dimensional drawings for exact locations of
the main power and control power entrance locations.
6. Terminals 24, 25, and 2 of the LVT are for the control of the
field-supplied LLSV. The maximum load allowed for the LLSV
is 15-va sealed and 30-va inrush at 24-v. Field power supply is
not required.
7. LLSV (24-v) should be 15-va maximum per valve as required.
8. Installation of fan status switch (FS1) is recommended.
9. The contacts for remote ON/OFF, fan status, and demand limit
options must be rated for dry circuit application capable of handling a 24-vac load up to 50 mA.
ALM R— Alarm Relay (24-v), 5-va Maximum
COOL1— Thermostat Stage 1 (24-v)
COOL2— Thermostat Stage 2 (24-v)
FS1— Fan Status Switch (24-v)
LLSV— Liquid Line Solenoid Valve
LV T— Low Voltage Terminal
MAT— Mixed Air Temperature Sensor
RAT— Return Air Temperature Sensor
SA— Set Point Adjustment (T-56, T-59)
SAT— Supply Air Temperature Sensor
SPT— Space Temperature Sensor (T-55, T-56, T-59)
Field Control Wiring
LV T
TERMINAL
121110987654321
25242322212019181716151413
STRIP
–
+
TEMP
RESET
4-20 mA
–
+
–
+
DEMAND LIMIT STEP 1
DEMAND LIMIT STEP 2
DEMAND
LIMIT
4-20 mA
COOLING
SETPOINT/
CAPACITY
REQUESTED
4-20 mA
16
Display Module Usage
Run Status
Service Test
Temperature
Pressures
Setpoints
Inputs
Outputs
Configuration
Time Clock
Operating Modes
Alarms
Alarm Status
ENTER
MODE
ESCAPE
Fig. 18 — Scrolling Marquee Display
ESCAPE
ENTER
ESCAPE
ESCAPE
ENTER
ESCAPE
ENTER
ENTER
ENTER
ENTER
ENTER
ENTER
ESCAPE
ENTER
ESCAPE
ESCAPE
ENTER
ESCAPE
ENTER
ESCAPE
ESCAPE
ENTER
ENTER
ENTER
ENTER
ESCAPE
ENTER
R
un
S
ta
tu
s
S
er
vic
e
T
e
s
t
T
e
m
pe
ra
tu
r
e
s
P
res
s
u
res
S
e
tpo
ints
Inp
u
ts
O
u
tpu
ts
C
o
nfig
u
ratio
n
T
im
e
C
lo
ck
O
p
e
ra
tin
g
M
o
d
e
s
A
la
rm
s
EN
TER
ES
C
M
O
D
E
Alarm Status
Comfort
Link
Fig. 19 — Accessory Navigator Display Module
SCROLLING MARQUEE DISPLAY — Thisdevice is the
keypad interface used for accessing unit information, reading
sensor values, and testing the unit. See Fig. 18. The scrolling
marquee display is a 4-key, 4-character, 16-segment LED
(light-emitting diode) display. Eleven mode LEDs are located
on the display as well as an Alarm Status LED. See Appendix
A — Display Tables for further details.
The scrolling marquee display module provides the user interface to the ComfortLink™ control system. The display has
up and down arrow keys, an key, and an
key. These keys are used to navigate through the different levels of the display structure. See Table 2. Press the
key until the display is blank to move through the top 11 mode
levels indicated by LEDs on the left side of the display.
Pressing the and keys simultaneously
will scroll a clear language text description across the display
indicating the full meaning of each display acronym. Pressing
the and keys when the display is blank
(Mode LED level) will return the scrolling marquee display to
its default menu of rotating display items. In addition, the password will be disabled requiring that it be entered again before
changes can be made to password protected items. Clear language descriptions will be displayed in English.
When a specific item is located, the display will flash showing the operator, the item, followed by the item value and then
followed by the item units (if any). Press the key to
stop the display at the item value. Items in the Configuration
and Service Test modes are password protected. The display
will flash PASS and WORD when required. Use the
and arrow keys to enter the 4 digits of the password. The
default password is 1111.
Changing item values or testing outputs is accomplished in
the same manner. Locate and display the desired item. Press
to stop the display at the item value. Press the
key again so that the item value flashes. Use the
arrow keys to change the value or state of an item and press the
key to accept it. Press the key and the
item, value, or units display will resume. Repeat the process as
required for other items.
ACCESSORY NAVIGATOR™ DISPLAY MODULE —
The Navigator module provides a mobile user interface to the
ComfortLink™ control system, which is only available as a
field-installed accessory. The display has up and down arrow
keys, an key, and an key. These keys are
used to navigate through the different levels of the display
structure. Press the key until ‘Select a Menu Item’
is displayed to move through the top 11 mode levels indicated
by LEDs on the left side of the display. See Fig. 19.
Once within a Mode or sub-mode, a “>” indicates the cur-
rently selected item on the display screen. Pressing the
and keys simultaneously will put the Navigator module into expanded text mode where the full meaning
of all sub-modes, items and their values can be displayed. Pressing the and keys when the display says
‘Select Menu Item’ (Mode LED level) will return the Navigator
module to its default menu of rotating display items (those items
in Run Status
VIEW). In addition, the password will be disabled, requiring that it be entered again before changes can be
made to password protected items. Press the key to
exit out of the expanded text mode.
NOTE: When the Language Selection (ConfigurationDISPLANG), variable is changed, all appropriate display
expansions will immediately change to the new language. No
power-off or control reset is required when reconfiguring
languages.
When a specific item is located, the item name appears on the
left of the display, the value will appear near the middle of the
display and the units (if any) will appear on the far right of the
display. Press the key at a changeable item and the value will begin to flash. Use the up and down arrow keys to change
the value, and confirm the value by pressing the key.
Changing item values or testing outputs is accomplished in
the same manner. Locate and display the desired item. Press
so that the item value flashes. Use the arrow keys to
change the value or state and press the key to accept
it. Press the key to return to the next higher level of
structure. Repeat the process as required for other items.
Items in the Configuration and Service Test modes are password protected. The words Enter Password will be displayed
when required, with 1111 also being displayed. The default
password is 0111. Use the arrow keys to change the number
and press to enter the digit. Continue with the remaining digits of the password. The password can only be
changed through CCN operator interface software such as
ComfortWORKS
®
, ComfortVIEW™ and Service Tool.
17
Adjusting the Contrast
ESCAPE
ENTER
ENTER
ENTER
ENTER
ESCAPE
ENTER
ESCAPE
ENTER
ENTER
ENTER
ENTER
— The contrast of the display can be
adjusted to suit ambient conditions. To adjust the contrast of
the Navigator module, press the key until the display reads, “Select a menu item.” Using the arrow keys move
to the Configuration mode. Press to obtain access to
this mode. The display will read:
> TEST OFF
METR OFF
LANG ENGLISH
Pressing will cause the “OFF” to flash. Use the up
or down arrow to change “OFF” to “ON”. Pressing
will illuminate all LEDs and display all pixels in the view
screen. Pressing and simultaneously
allows the user to adjust the display contrast. Use the up or
down arrows to adjust the contrast. The screen’s contrast will
change with the adjustment. Press to accept the
change. The Navigator module will keep this setting as long as
it is plugged in to the LEN bus.
Adjusting the Backlight Brightness
— The backlight of the
display can be adjusted to suit ambient conditions. The factory
default is set to the highest level. To adjust the backlight of the
Navigator module, press the key until the display
reads, “Select a menu item.” Using the arrow keys move to the
Configuration mode. Press to obtain access to this
mode. The display will read:
> TEST OFF
METR OFF
LANG ENGLISH
Pressing will cause the “OFF” to flash. Use the up
or down arrow keys to change “OFF” to “ON”. Pressing
will illuminate all LEDs and display all pixels in the
view screen. Pressing the up and down arrow keys simultaneously allows the user to adjust the display brightness. Use the
up or down arrow keys to adjust screen brightness. Press
to accept the change. The Navigator module will
keep this setting as long as it is plugged in to the LEN bus.
Main Base Board (MBB) — See Fig. 20. The MBB is
the heart of the ComfortLink control system. It contains the
major portion of operating software and controls the operation
of the machine. The MBB continuously monitors input/output
channel information received from its inputs and from all other
modules. The MBB receives inputs from the discharge and
suction pressure transducers, current sensor boards (CSB) and
thermistors. See Table 3. The MBB also receives the discrete
inputs from the thermostat contacts and other status switches.
See Table 4. The MBB also controls several outputs. Information is transmitted between modules via a 3-wire communication bus or LEN (Local Equipment Network). The CCN (Carrier Comfort Network
®
) bus is also supported. Connections to
both LEN and CCN buses are made at the LVT (low voltage
terminal) terminal strip.
Current Sensor Board (CSB) — The CSB is used to
monitor the status of the compressors by measuring current and
providing an analog input to the main base board (MBB) or
compressor expansion module (CXB).
Energy Management Module (EMM) — The EMM
module is available as a factory-installed option or as a fieldinstalled accessory. The EMM module receives 4 to 20 mA
inputs for the percent capacity, temperature reset, cooling set
point, and demand limit functions. The EMM module also receives the switch inputs for the field-installed 2-stage demand
limit and when two thermostats are used for one unit. The
EMM module communicates the status of all inputs with the
MBB, and the MBB adjusts the control point, capacity limit,
and other functions according to the inputs received.
Table 2 — Scrolling Marquee Display Menu Structure*
MODE
SUB-MODE
LEGEND
Ckt — Circuit
*Throughout this text, the location of items in the menu structure will be described in
the following format:
Item Expansion (Mode Name Sub-mode N ame ITEM)
RUN
STATUS
Auto
Display
(VIEW)
Machine
Hours/Starts
(RUN)
Compressor
Run Hours
(HOUR)
Compressor
Starts
(STRT)
Preventive
Maintenance
(PM)
Software
Ver si on
(VERS)
SERVICE
TEST
Manual
Mode
On/Off
(TEST)
Unit
Outputs
(OUTS)
Ckt A Comp
Tests
(CMPA)
Ckt B Comp
Tests
(CMPB)
TEMPERATURES PRESSURES
Unit
Temperatures
(UNIT)
Ckt A
Temperatures
(CIR.A)
Ckt B
Temperatures
(CIR.B)
Ckt A
Pressures
(PRC.A)
Ckt B
Pressures
(PRC.B)
SET
POINTS
Cooling
(COOL)
Head
Pressure
(HEAD)
INPUTS OUTPUTS CONFIGURATION
Unit
Discrete
(GEN.I)
Ckt A/B
(CRCT)
Unit
Analog
(4-20)
Unit
Discrete
(GEN.O)
Ckt A
(CIR.A)
Ckt B
(CIR.B)
Display
(DISP)
Unit Configuration
(UNIT)
CCN Network
(CCN)
Options 1
(OPT1)
Options 2
(OPT2)
Motormaster
(M.MST)
Reset Cool
Temperature
(RSET)
Set Point Select
(SLCT)
Service
Configuration
(SERV)
Broadcast
Configuration
(BCST)
TIME
CLOCK
Unit Time
(TIME)
Unit Date
(DATE)
Daylight
Saving
Time
(DST)
Local
Holiday
Schedules
(HOL.L)
Schedule
Number
(SCH.N)
Local
Schedule
Number
(SCH.L)
Schedule
Overide
(OVR)
OPERATING
MODES
Modes
(MODE)
Task State
(TSKS)
ALARMS
Current
(CRNT)
Reset
Alarms
(RCRN)
Alarm
History
(HIST)
18
Table 3 — Thermistor Designations
CEPL130346-01
STATUS
LEN
J1
J2
J4
J3
J5
J6
J7
J8
J9
J10
CCN
RED LED - STATUSGREEN LED -
LEN (LOCAL EQUIPMENT NETWORK)
YELLOW LED CCN (CARRIER COMFORT NETWORK)
INSTANCE JUMPER
K11
K10K9
K8
K7
K6
K5
K4
K3K2
K1
Fig. 20 — Main Base Board
THERMISTOR INPUTPIN CONNECTION POINT
Return Air (Accessory)MBB J8-11,12; LVT 19,20
Supply Air (Accessory)MBB J8-12,13; LVT 11,19
Compressor Return Gas
Temperature A
Compressor Return Gas
Temperature B
Outdoor Air TemperatureMBB J8-7,8
Discharge Temperature
(Digital Option Only)
Space Temperature (Accessory)MBB J8-5,6; LVT 21,22
Table 4 — Switch Inputs
Thermostat Y1 (Accessory)LVT 12,18
Thermostat Y2 (Accessory)LVT 15,18
Fan Status 1 (Accessory)LVT 16,18
Fan Status 2 (Accessory)LVT 17,18
Remote On/OffLVT 13,14
High Pressure Switch AMBB J6-4
High Pressure Switch BMBB J6-6
SWITCH INPUTPIN CONNECTION POINT
Compressor Expansion Module (CXB) — The
CXB is only used on unit sizes 070-100 to provide additional
inputs and outputs for fans and compressors when the unit has
more than 4 compressors.
AUX Board (AUX) — The AUX is used with the digital
scroll option and the low ambient head pressure option. It provides additional inputs and outputs for digital scroll control
along with analog outputs to control head pressure control fan
speeds.
Enable/Off/Remote Contact Switch — The Enable/
Off/Remote Contact switch is a 3-position switch used to
control the unit. When switched to the Enable position, the unit
is under its own control. Move the switch to the Off position to
shut the unit down. Move the switch to the Remote Contact position and a field-installed dry contact can be used to start the
unit. The contacts must be capable of handling a 24 vac, 50 mA
load. In the Enable and Remote Contact (dry contacts closed)
MBB J8-1,2
MBB J8-3,4
AUX J6- 1, 2
positions, the unit is allowed to operate and respond to the
scheduling configuration, CCN configuration and set point
data. See Fig. 21.
Emergency On/Off Switch — The Emergency On/Off
switch should only be used when it is required to shut the
unit off immediately. Power to the MBB, CXB, AUX, EMM,
and scrolling marquee display is interrupted when this switch is
off and all outputs from these modules will be turned off.
Board Addresses — The main base board (MBB) has a
3-position Instance jumper that must be set to ‘1.’ All other
boards have 4-position DIP switches. All switches are set to
‘On’ for all boards.
Control Module Communication
RED LED — Proper operation of the control boards can be
visually checked by looking at the red status LEDs
(light-emitting diodes). When operating correctly, the red status
LEDs should be blinking in unison at a rate of once every
2 seconds. If the red LEDs are not blinking in unison, verify
that correct power is being supplied to all modules. Be sure that
the main base board (MBB) is supplied with the current software. If necessary, reload current software. If the problem still
persists, replace the MBB. A red LED that is lit continuously or
blinking at a rate of once per second or faster indicates that the
board should be replaced.
GREEN LED — The MBB has one green LED. The Local
Equipment Network (LEN) LED should always be blinking
whenever power is on. All other boards have a LEN LED
which should be blinking whenever power is on. Check LEN
connections for potential communication errors at the board J3
and/or J4 connectors. Communication between modules is
accomplished by a 3-wire sensor bus. These 3 wires run in
parallel from module to module. The J4 connector on the MBB
provides both power and communication directly to the
marquee display only.
YELLOW LED — The MBB has one yellow LED. The
Carrier Comfort Network (CCN) LED will blink during times
of network communication.
The 38AP units can be connected to the CCN if desired. The
communication bus wiring is a shielded, 3-conductor cable
with drain wire and is supplied and installed in the field. See
Table 5. The system elements are connected to the communication bus in a daisy chain arrangement. The positive pin of
each system element communication connector must be wired
to the positive pins of the system elements on either side of it.
This is also required for the negative and signal ground pins of
each system element. Wiring connections for CCN should be
made at LVT. Consult the CCN Contractor’s Manual for further information.
NOTE: Conductors and drain wire must be 20 AWG (American Wire Gage) minimum stranded, tinned copper. Individual
conductors must be insulated with PVC, PVC/nylon, vinyl,
Teflon, or polyethylene. An aluminum/polyester 100% foil
shield and an outer jacket of PVC, PVC/nylon, chrome vinyl,
or Teflon with a minimum operating temperature range of
–20 C to 60 C is required. Wire manufactured by Alpha (2413
or 5463), American (A22503), Belden (8772), or Columbia
(02525) meets the above mentioned requirements.
It is important when connecting to a CCN communication
bus that a color coding scheme be used for the entire network
to simplify the installation. It is recommended that red be used
for the signal positive, black for the signal negative, and white
for the signal ground. Use a similar scheme for cables containing different colored wires.
At each system element, the shields of its communication
bus cables must be tied together. If the communication bus is
entirely within one building, the resulting continuous shield
must be connected to a ground at one point only. If the communication bus cable exits from one building and enters another,
the shields must be connected to grounds at the lightning
suppressor in each building where the cable enters or exits the
building (one point per building only). To connect the unit to
the network:
1. Turn off power to the control box.
2. Cut the CCN wire and strip the ends of the red (+), white
3. Connect the red wire to (+) terminal on LVT of the plug,
(ground), and black (–) conductors. (Substitute appropriate colors for different colored cables.)
the white wire to COM terminal, and the black wire to the
(–) terminal.
20
4. The RJ14 CCN connector on LVT can also be used, but is
only intended for temporary connection (for example, a
laptop computer running Service Tool).
IMPORTANT: A shorted CCN bus cable will prevent some
routines from running and may prevent the unit from starting. If abnormal conditions occur, unplug the connector. If
conditions return to normal, check the CCN connector and
cable. Run new cable if necessary. A short in one section of
the bus can cause problems with all system elements on the
bus.
Sensors — The electronic control uses 3 to 7 thermistors to
sense temperatures for controlling unit operation. See Table 3.
These sensors are outlined below. Three different thermistor
curves are utilized depending on the thermistor and the configuration of the input. The three different types are 5 kat 77 F
(25 C), 10 kat 77 F (25 C), and 86 k at 77 F (25 C). See
Thermistors section on page 49 for additional information.
RETURN AIR TEMPERATURE (RAT) ACCESSORY
(Part No. 33ZCSENSAT) — A return air temperature sensor
is required for unit sizes 040-100 and all units equipped with
the digital scroll option. The sensor is field installed in the
indoor unit and wired to the LVT of the unit to measure the air
temperature entering the evaporator coil. The sensor should be
located directly in front of the evaporator coil after an outside
air intake.
The RAT sensor consists of a thermistor encased within a
stainless steel probe. See Fig. 22. The sensor probe is 6 in.
nominal length with 114 in. of unshielded, 2-conductor
18 AWG twisted-pair cables. The sensor temperature range is
–40 to 245 F with a nominal resistance of 10,000 ohms at 77 F.
The sensor has with an accuracy of ±0.36 F.
Fig. 22 — 33ZCSENSAT Sensor
.39
.08
FOAM GASKET
.40'' O.D.
.250 ±.01 Dia
5.5 ±.5
PLENUM RATED CABLE
114'' ±6
3.00
3.90
.175 DIA
x .600
NOTE: All dimensions
shown in inches.
2
3
45
61
SW1
SEN
BRN (GND)
BLU (SPT)
RED(+)
WHT(GND)
BLK(-)
CCN COM
SENSOR WIRING
Fig. 23 — Space Temperature Sensor
Typical Wiring (33ZCT55SPT)
2
3
45
61
SW1
SEN
SET
CoolWarm
BRN (GND)
BLU (SPT)
RED(+)
WHT(GND)
BLK(-)
CCN COM
SENSOR WIRING
JUMPER
TERMINALS
AS SHOWN
BLK
(T56)
Fig. 24 — Space Temperature Sensor
Typical Wiring (33ZCT56SPT)
SUPPLY AIR TEMPERATURE (SAT) ACCESSORY
(33ZCSENSAT) — A supply air temperature sensor is
required for unit sizes 040-100 and all units equipped with the
digital scroll option. The SAT sensor consists of a thermistor
encased within a stainless steel probe. See Fig. 22. The SAT
sensor probe is 6 in. nominal length with 114 in. of unshielded,
2-conductor 18 AWG twisted-pair cables. The sensor temperature range is –40 to 245 F with a nominal resistance of
10,000 ohms at 77 F. The sensor has an accuracy of ±0.36 F.
NOTE: The sensor must be mounted in the discharge of the
unit, downstream of the cooling coil and before any heating
coil or heat exchanger if reheat is utilized. Be sure the probe tip
does not come in contact with any of the unit surfaces.
COMPRESSOR RETURN GAS TEMPERATURE SENSOR (RGT) — These sensors are factory installed in a friction fit well located in the suction line of each circuit. They are
a 5 k thermistor connected to the main base board.
OUTDOOR-AIR TEMPERATURE SENSOR (OAT) —
This sensor is factory installed on a bracket which is inserted
through the base pan of the unit on the unit sizes 025-060 and
mounted to the back of the control box on the unit sizes 070-
100. This sensor is a 5 k thermistor connected to the main
base board.
DISCHARGE TEMPERATURE THERMISTOR
(DTT) — This sensor is only used on units with a digital
compressor. The sensor is mounted on the discharge line close
to the discharge of the digital compressor. It attaches to the discharge line using a spring clip and protects the system from
high discharge gas temperature when the digital compressor is
used. This sensor is a 86 k thermistor connected to the AUX
board.
SPACE TEMPERATURE SENSOR (SPT) — The space
temperature sensors are used to measure the interior
temperature of a building. The following three types of SPT
sensors are available:
• Space temperature sensor (33ZCT55SPT) with timed
override button (see Fig. 23)
• Space temperature sensor (33ZCT56SPT) with timed
override button and set point adjustment (see Fig. 24)
• Space temperature sensor (33ZCT59SPT) with occupancy override button, set point adjustment slidebar, and
LCD (liquid crystal display) display
The sensor should be mounted approximately 5 ft from the
floor in an area representing the average temperature in the
space. Allow at least 4 ft between the sensor and any corner.
Mount the sensor at least 2 ft from an open doorway.
To connect the space temperature sensor (Fig. 25):
1. Use a 20 gage wire to connect the sensor to the controller.
The wire is suitable for distances of up to 500 ft. Use a
three-conductor shielded cable for the sensor and set
point adjustment connections. The standard CCN
communication cable may be used. If the set point
adjustment (slidebar) is not required, then an unshielded,
18 or 20 gage, two-conductor, twisted pair cable may be
used. Connect one wire of the twisted pair to one SEN
terminal and connect the other wire to the other SEN terminal located under the cover of the space temperature
sensor.
2. Connect the other ends of the wires to terminals 21 and
22 on LVT located in the unit control box.
3. Connect the T56 set point adjustment between the SET
terminal and LVT terminal 23.
21
Units on the CCN can be monitored from the space using
Fig. 25 — Typical SPT Wiring
T-55 SPACE
SENSOR
CCN+
CCN GND
CCN-
TO CCN
COMM 1
BUS (PLUG)
AT UNIT
1
2
3
4
5
6
Fig. 26 — CCN Communications Bus Wiring to
Optimal Space Sensor RJ11 Connector
J6
6
7
RED
BLK
RED
RED
BLK
BLK
BLK
RED
BLK
RED
SENSOR 1SENSOR 2SENSOR 3SENSOR 4
J6
6
7
RED
BLK
RED
BLK
SENSOR 2
SENSOR 1
RED
RED
BLK
SENSOR 3
SENSOR 4
BLK
BLK
RED
RED
RED
BLK
BLK
SENSOR 8
SENSOR 9
SENSOR 5
RED
BLK
SENSOR 6
SENSOR 7
BLK
RED
SPACE TEMPERATURE AVERAGING — 4 SENSOR APPLICATION
Fig. 27 — Space Temperature Averaging
LEGEND
Factory Wiring
Field Wiring
SPACE TEMPERATURE AVERAGING — 9 SENSOR APPLICATION
the RJ11 connector provided with the space sensor, if desired.
To wire the RJ11 connector into the CCN (Fig. 26):
IMPORTANT: The cable selected for the RJ11 connector
wiring MUST be identical to the CCN communication bus
wire used for the entire network. Refer to Table 5 for
acceptable wiring.
1. Cut the CCN wire and strip ends of the red (+), white
(ground), and black (–) conductors. (If another wire color
scheme is used, strip ends of appropriate wires.)
2. Insert and secure the red (+) wire to terminal 5 of the
space temperature sensor terminal block.
3. Insert and secure the white (ground) wire to terminal 4 of
the space temperature sensor.
4. Insert and secure the black (–) wire to terminal 2 of the
space temperature sensor.
5. Connect the other end of the communication bus cable to
the remainder of the CCN communication bus.
NOTE: See Fig. 27 for space temperature averaging.
SEN
SPT
SENSOR
SEN
SET
LVT
21
22
23
22
Fan Status Input — A proof-of-fan operation is recom-
CEBD430351-0396-01C
TEST 1
CEPL130351-01
PWR
TEST 2
J1
J2
J4J3
J5
J6
J7
LEN
STATUS
RED LED - STATUS
GREEN LED LEN (LOCAL EQUIPMENT NETWORK)
ADDRESS
DIP SWITCH
Fig. 28 — Energy Management Module
mended and needs to be field installed in the indoor unit. Several different types of switches can be utilized, such as a differential pressure switch located across the indoor fan or auxiliary
contacts on an indoor fan contactor.
Thermostat Input — A two-stage thermostat can be
used for constant volume applications to provide Y1 and Y2
cooling inputs.
Pressure Transducer Inputs — Each refrigerant cir-
cuit is equipped with a suction and discharge pressure transducer. The suction pressure transducers have a yellow body
with a pressure range of -6.7 to 420 psig while the discharge
transducers have a red body with a pressure range of 14.5 to
667 psig. These inputs connect to the MBB (main base board)
and are used to monitor the status of the unit and to ensure the
unit operates within the compressor envelope. The transducers
are used to protect the compressor from operating at too low or
too high of a pressure condition. In some cases, the unit may
not be able to run at full capacity. The MBB will automatically
reduce the capacity of a circuit as needed to maintain specified
maximum/minimum operating pressures.
Energy Management Module (Fig. 28) — The
energy management module (EMM) is a factory-installed option (FIOP) or field-installed accessory used for the following
types of temperature reset, demand limit, and capacity control
features:
• 4 to 20 mA temperature reset
• 4 to 20 mA cooling set point
• 4 to 20 mA desired capacity set point
• 4 to 20 mA demand limit
• Discrete inputs for 2-step demand limit (requires fieldsupplied dry contacts capable of handling a 24 vac,
50 mA load)
• Discrete inputs for units with dual thermostats
NOTE: A field-supplied 4 to 20 mA signal generator is required for use with the EMM.
See VAV Supply Air Temperature Reset and Demand Limit
sections on pages 29 and 31 for further details.
CAUTION
Care should be taken when interfacing with other manufacturer’s control systems due to possible power supply
differences, full wave bridge versus half wave rectification.
The two different power supplies cannot be mixed.
ComfortLink™ controls use half wave rectification. A
signal isolation device should be utilized if a full wave
bridge signal generating device is used.
Control — When mechanical cooling is required, the MBB
has the capability to control the unit capacity by staging multiple scroll compressors and controlling the digital scroll compressor operation. The control also checks on various other operation parameters in the unit to make sure that safeties are not
exceeded and the compressors are reliably operated.
The ComfortLink™ control system offers two basic control
approaches to mechanical cooling; constant volume operation
for 2 stages of cooling or VAV operation for multiple stages
of cooling. In addition to these methods of control, the
ComfortLink control offers the ability to run multiple stages of
cooling for either a space temperature sensor or thermostat
control by controlling the unit to either a low or high cool set
point. The control type ConfigurationOPT2C.TYP determines the selection of the type of cooling control as well as
the method for selecting a cooling mode.
SETTING UP THE SYSTEM
Machine Control Type (
— The most important cooling control configuration is located
under ConfigurationOPT2. This configuration defines the
method and control source responsible for selecting a cooling
mode. The configuration also determines the method by which
compressors are staged. Control types are:
• C.TYP = 1 (VAV-RAT) configuration refers to standard
VAV operation.
ConfigurationOPT2 C.TYP)
23
Fig. 29 — Space Temperature vs.
Space Temperature Set Point
A48-7701
• C.TYP = 3 (TSTAT-MULTI) configuration will force
the MBB to monitor the thermostat inputs to make a
determination of mode. Unlike traditional 2-stage thermostat 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 set point or a high
set point to maintain supply air temperature. (Required
for 025-030 units with digital scroll option and 040-100
units with two-stage thermostat control.)
• C.TYP = 4 (TSTAT-2STG) configuration will force the
MBB to monitor the thermostat inputs to make a determination of mode.
• C.TYP = 5 (SPT-MULTI) configuration will force the
MBB 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 set point or
a high set point to maintain supply air temperature.
• C.TYP = 7 (% CAPACITY) configuration will force the
MBB to monitor the 4-20 cooling demand CL.MA input
and translate this into desired % capacity for the unit.
• C.TYP = 9 (VAV-SETPOINT) configuration will force
the MBB to monitor the 4-20 cooling demand CL.MA
input. This value will be translated into a desired leaving-air set point ranging from 40 to 80 F. The control will
translate the input linearly with 4 ma equal to 40 F set
point and 20 mA equal to 80 F set point.
Unit Capacity Control Based on Unit Type
— The MBB
uses several set points to control capacity depending on unit
type. The set points are located in the set point area of the display SetPointsCOOL. Refer to Table 6 and the following
descriptions.
Table 6 — Unit Capacity Control
ITEMDESCRIPTIONRANGE UNITS DEFAULT
CSP1 Cooling Set Point 140-80F65
CSP2 Cooling Set Point 240-80F55
SPS.P Space Temperature Cooling Set
Poin t
L.C.ON Demand Level Low Cool On–1-2^F1.5
H.C.ON Demand Level (+) High Cool On 0.5-20.0^F0.5
L.C.OF Demand Level (–) Low Cool Off0.5-2^F1
65-80F74
• C.TYP = 1 (VAV-RAT) is a capacity control routine that
controls compressor capacity to supply air temperature.
The MBB will attempt to control leaving temperature to
the control point (CTPT) which equals CSP1 plus any
reset which is being applied.
• C.TYP = 3 (TSTAT-MULTI) configuration will force the
MBB to monitor the thermostat inputs to make a determination of control point (CTPT). The control will vary
the control point based on Y1 and Y2 inputs. When Y1 is
closed CSP1 will be used and when Y2 is closed CSP2
will be used as the supply air temperature set point.
CSP1 should be greater than CSP2.
• C.TYP = 4 (TSTAT-2STG) configuration will force the
MBB to monitor the thermostat inputs to make a determination of mode and capacity. If Y1 input is closed,
50% of the unit capacity will be energized and if Y2 is
closed, 100% of the unit capacity will be energized.
NOTE: This is not a preferred method of control for units
with greater than 2 stages of capacity
• C.TYP = 5 (SPT-MULTI) configuration will force the
MBB to monitor the thermostat inputs to determine
mode and cooling set point as the unit is controlled by
space temperature vs space temperature set point SPS.P.
Unlike traditional 2-stage thermostat 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 set point (CSP1) or high set point (CSP2) for
supply air depending on space temperature vs space
temperature set point. The control uses SPS.P, LC.ON,
HC.ON, and LC.OF to determine the leaving set point.
LC.ON and HC.ON are added to the space temperature
set point to determine when cooling mode will begin and
when CSP1 and CSP2 will be used for leaving set point.
Based on LC.OF, the control point transitions betweenCSP1 and CSP2. LC.OF is used to calculate the space temperature at which control point is raised based on space temperature vs space temperature set point (SPS.P) plus
LC.ON minus LC.OF. The control point transition from
CSP2 to CSP1 occurs when space temperature is below
LC.OF divided by 2.
For example (see Fig. 29):
Given: SPS.P = 72 F, LC.ON = 1, HC.ON = 3,
LC.OF = 2 F, CSP1 = 60 F, and CSP2 = 55 F
If space temperature equals 73 F (72+1) (Low Cool)
cooling will begin and control set point equals 60 F
(CSP1).
If space temperature is greater than 76 F (72+1+3 = 76)
(High Cool), control point set point would equal 55 F
(CSP2).
If space temperature falls below 72 F (73-2/2) (Low
Cool minus LC.OF/2), control point transitions back to
60 F CSP1 if space continues to fall below 71 F (73-2)
(Low Cool minus LC.OF), the unit is shut off.
76 F
H.C.ON
73 F
L.C.ON
L.C. OF
Cooling Setpoint
L.C. OF/2
Hi Cool End 72 F72 F
Lo Cool End 71 F
• C.TYP = 7 (% CAPACITY) configuration will force the
MBB to monitor the input 4-20 cooling demand CL.MA
and translate this into desired % capacity for the unit.
The control will attempt to match the desired capacity
insuring the unit operates the compressor within compressor safeties and timeguards. (Requires the EMM
option or accessory.)
• C.TYP = 9 (VAV-SETPOINT) configuration will force
the MBB to operate as a VAV unit and control capacity to
meet supply air temperature. The control point is developed from the 4-20 cooling demand CL.MA input value.
The 4 to 20 mA input will be translated into a desired
control point ranging from 40 to 80 F. The control will
translate the input linearly with 4 mA equal to 40 F set
point and 20 mA equal to 80 F set point. (Requires the
EMM option or accessory.)
Capacity Control Logic when Control is Controlling to Supply Temperature — The control system cycles compressors,
hot gas bypass and the digital compressor to maintain the supply temperature at or close to the control point of the unit. The
SAT and RAT sensors are used by the main base board (MBB)
to determine the temperature drop across the evaporator and
are used in determining the optimum time to add or subtract capacity stages. The CSP set points can be automatically reset by
24
Hi Cool Start
Lo Cool Start
the return temperature, space, or outdoor-air temperature reset
features. It can also be reset from an external 4 to 20 mA signal
(requires energy management module factory-installed option
or field-installed accessory).
The control has an automatic lead-lag feature built in which
determines the wear factor (combination of starts and run
hours) for each compressor. If all compressors are off and less
than 30 minutes has elapsed since the last compressor was
turned off, the wear factor is used to determine which compressor to start next. As additional stages of compression are required, the processor control will add them. If a circuit is to be
stopped, the compressor with the lowest wear factor will be
The capacity control algorithm runs every 30 seconds. The
algorithm attempts to maintain the control point at the desired
set point. Each time it runs, the control reads the entering and
leaving temperatures. The control determines the rate at which
conditions are changing and calculates 2 variables based on
these conditions. Next, a capacity ratio is calculated using the
2 variables to determine whether or not to make any changes to
the current stages of capacity. This ratio value ranges from
–100 to +100%. If the next stage of capacity is a compressor,
the control starts (stops) a compressor when the ratio reaches
+100% (-100%). A delay of 90 seconds occurs after each capacity step change. Refer to Table 8.
shut off first. See Table 7 for compressor size information and
Table 8 for compressor loading sequence.
2. When unit is equiped with digital scroll option, sequence A is always
used.
25
MINUTES LEFT FOR START — This value is displayed
only in the network display tables (using Service Tool,
ComfortVIEW™ or ComfortWORKS
®
software) and
represents the amount of time to elapse before the unit will start
its initialization routine. This value can be zero without the
machine running in many situations. This can include being
unoccupied, ENABLE/OFF/REMOTE CONTACT switch in
the OFF position, CCN not allowing unit to start, Demand
Limit in effect, no call for cooling due to no load, and alarm or
alert conditions present. If the machine should be running and
none of the above are true, a minimum off time (DELY, see
below) may be in effect. The machine should start normally
once the time limit has expired.
MINUTES OFF TIME (ConfigurationOPT2
DELY) — This user-configurable time period is used by
the control to determine how long unit operation is delayed
after power is applied/restored to the unit. Typically, this time
period is configured when multiple machines are located on a
single site. For example, this gives the user the ability to prevent all the units from restarting at once after a power failure.
A value of zero for this variable does not mean that the unit
should be running.
NOTE: If the unit has digital scroll or hot gas bypass, circuit A
is always lead.
LEAD/LAG DETERMINATION — This is a configurable
choice and is factory set to be automatic for all units. The value
can be changed to Circuit A or Circuit B leading as desired. Set
at automatic, the control will sum the current number of logged
circuit starts and one-quarter of the current operating hours for
each circuit. The circuit with the lowest sum is started first.
Changes to which circuit is the lead circuit and which is the lag
are also made when total machine capacity is at 100% or when
there is a change in the direction of capacity (increase or
decrease) and each circuit’s capacity is equal.
CAPACITY CONTROL OVERRIDES — The following overrides will modify the normal operation of the routine.
Deadband Multiplier
— The user configurable deadband mul-
tiplier (ConfigurationSLCTZ.GN) has a default value of
1.0. The range is from 1.0 to 4.0. When set to other than 1.0,
this factor is applied to the capacity Load/Unload Factor. The
larger this value is set, the longer the control will delay between
adding or removing stages of capacity.
First Stage Override
— If the current capacity stage is zero,
the control will modify the routine with a 1.2 factor on adding
the first stage to reduce cycling. This factor is also applied
when the control is attempting to remove the last stage of
capacity.
Slow Change Override
— This control prevents the capacity
stages from being changed when the supply temperature is
Table 9 — Fan Stages
38AP UNIT SIZE
025-030
040,050
060
070
080
090,100
* Fan Stage 1 on unit size 070 is used only when ambient temperature is less than 32 F.
CIRCUIT A STAGES/COMMON FAN STAGESCIRCUIT B FAN STAGES
Fan StageContactor EnergizedFans OperatingFan StageContactor EnergizedFans Operating
Stage 1
Stage 2
Stage 1
Stage 2
Stage 3
Stage 1
Stage 2
Stage 3
Stage 4
Stage 1*
Stage 2
Stage 3
Stage 1
Stage 2
Stage 1
Stage 2
Stage 3
Stage 4
Stage 5
Stage 6
FC1
FC1,2
FC1
FC2
FC1,2
FC1
FC2
FC1,2
FC1,2,3
FC2,4
FC1
FC1,3
FC1
FC1,3
FC4
FC1
FC4,1
FC4,3
FC1,3
FC4,1,3
OFM1
OFM1,2
OFM3
OFM1,2
OFM1,2,3
OFM3
OFM1,2
OFM1,2,3
OFM1,2,3,4
OFM1,2
OFM3
OFM3,4
OFM5
OFM5,6,(2)
OFM3
OFM5
OFM3,5
OFM3,(2),4,6
OFM5,(2),4,6
OFM3,5,(2),4,6
close to the set point (within an adjustable deadband) and moving toward the set point.
Ramp Loading
— The ramp loading control (Configuration
SLCTCRMP) limits the rate of change of supply temperature. If the unit is in a Cooling mode and configured for Ramp
Loading, the control makes 2 comparisons before deciding to
change stages of capacity. The control calculates a temperature
difference between the control point and supply temperature. If
the difference is greater than 4° F (2.2° C) and the rate of
change (°F or °C per minute) is more than the configured Cooling Ramp Loading value (CRMP), the control does not allow
any changes to the current stage of capacity.
Minimum Load Control
— If equipped, the minimum load
control valve is energized only when one compressor on the
circuit is running and the unit is unloading.
Low Saturated Suction Protection
— The control will try to
prevent shutting a circuit down due to low saturated suction
conditions by removing stages of capacity. See Alerts section.
Head Pressure Control — The main base board
(MBB) controls the condenser fans to maintain the lowest
condensing temperature possible, and thus the highest unit
efficiency. The MBB uses the saturated condensing temperature input from the discharge pressure transducer and outside
air temperature sensor to control the fans. If OAT is greater
than 70 F before a circuit is starting, then all condenser fan
stages will be energized. A fan stage is increased based on
SCT. When the highest SCT of both circuits is greater than fan
on set point, then an additional stage of fan will be added to the
current fan stage. Fan On Set Point (F. O N ) equals Head Set
Point ON (115 F) except after a fan stage increase when Head
Set Point is increased by Fan Stage Delta (10 F). A fan stage is
decreased when the SCTs of both circuits are less than fan off
set point for two minutes. Fan Off Set Point (F. O F F ) equals
Head Set Point OFF (–72 F). Table 9 shows the number of fan
stages, contactors energized and the fans that are on during the
fan stage. Unit sizes 025 to 060 have common fan control. Unit
sizes 070 to 100 have some fans that are common and some
that are controlled individually. Figure 30 shows the location
of each fan and compressor within the unit.
MOTORMASTER
tion, the first stage of fans is equipped with the Motormaster V
head pressure controller option or accessory. For units with
common fans, the control will control the Head Pressure Setpoint (–10 F) and the highest SCT to try to maintain it at 100 F.
Unit sizes 070 to 100 have one Motormaster V for each circuit
and the control tries to maintain SCT at 100 F for the circuit.
The controller is given an ON command with the first stage of
fan and adjusts fan speed.
Stage 1*
Stage 2
Stage 3
Stage 1
Stage 2
Stage 3
Stage 1
Stage 2
Stage 3
Stage 4
Stage 5
Stage 6
®
V OPTION — For low-ambient opera-
———
———
———
FC1,3
FC2
FC2,4
FC4
FC3,4
FC2,3,4
FC4
FC2
FC4,2
FC4,3
FC2,3
FC4,2,3
OFM3,4
OFM1
OFM1,2
OFM3
OFM3,2,(6)
OFM3,1,2,(6)
OFM3
OFM1
OFM3,1
OFM3,2,4,(6)
OFM1,2,4,(6)
OFM3,1,2,4,(6)
26
Outdoor Fan Layout – Top View
Sizes 025-030Sizes 040, 050Sizes 060, 070
CONTROL BOX
CONTROL BOX
OFM1
OFM2OFM2
OFM3
OFM1
CONTROL BOX
OFM3
OFM4
OFM2
OFM1
Size 080Sizes 090, 100
CONTROL BOX
OFM2
OFM3
OFM5
OFM6
OFM1
CONTROL BOX
OFM4
OFM5
OFM6
OFM2
OFM3
OFM1
Compressor Layout Dual Circuit – Top View
Sizes 025-030Sizes 040-060Sizes 070, 080
CONTROL BOX
1
B1
CONTROL BOX
B1
B2
1
2
CONTROL BOX
B1
B2
2
1
B3
Sizes 090, 100
CONTROL BOX
B1
B2
B3
3
2
1
Sizes 025-030Sizes 040, 050
CONTROL BOX
CONTROL BOX
Compressor Layout Single Circuit – Top View
1
2
1
2
3
Fig. 30 — Compressor and Fan Location
A
A
A
A
A
A
A
A
A
A
A
A
A
27
Service Test — Both main power and control circuit
ENTER
ENTER
ESCAPE
power must be on.
The Service Test function should be used to verify proper
operation of condenser fan(s), compressors, minimum load
valve solenoid (if installed), liquid line solenoid valve (if
installed), and remote alarm relay. To use the Service Test
mode, the Enable/Off/Remote Contact switch must be in the
OFF position. Use the display keys and Service Test Mode and
Sub-Mode Directory table in Appendix A to enter the mode
and display TEST. Press twice so that OFF flashes.
Enter the password if required. Use either arrow key to change
the TEST value to the ON position and press . Place
the Enable/Off/Remote Contact switch in the ENABLE position. The Service Test mode is now enabled. Press
and the down key to enter the OUTS, COMPA or COMPB
sub-mode.
Test the condenser fans, liquid line solenoid and alarm relay by changing the item values from OFF to ON. These discrete outputs are then turned off if there is no keypad activity
for 10 minutes. When testing the digital output the display can
be changed from 1 to 15 by using either the up or down arrow;
the number represents the cycle rate out of a 15 second duty cycle that the output will be energized. If the cycle is set for 7, the
output will be energized 7 seconds out of every 15 seconds.
Test the compressor and minimum load valve solenoid (if installed) outputs in a similar manner. The minimum load valve
solenoids will be turned off if there is no keypad activity for
10 minutes. Compressors will stay on until they are turned off
by the operator. The Service Test mode will remain enabled for
as long as there is one or more compressors running. All safeties are monitored during this test and they will turn a compressor, circuit or the machine off if required. Any other mode or
sub-mode can be accessed, viewed, or changed during the
TEST mode. The STAT item (Run/StatusVIEW) will display "0" as long as the Service mode is enabled. The TEST
sub-mode value must be changed back to OFF before the unit
can be switched to Enable or Remote contact for normal
operation.
Operating Modes
RAMP LOAD LIMITED (MD05) — Ramp load (pulldown) limiting is in effect. In this mode, the rate at which supply fluid temperature is dropped is limited to a predetermined
value to prevent compressor overloading. See Cooling Ramp
Loading (ConfigurationSLCTCRMP). The pull-down
limit can be modified, if desired, to any rate from 0.2 to 2° F
(0.1 to 1° C) per minute.
TIMED OVERRIDE IN EFFECT (MD06) — Timed override is in effect. This is a 1 to 4 hour temporary override of the
programmed schedule, forcing unit to Occupied mode. Override can be implemented with unit under Local (Enable) or
CCN (Carrier Comfort Network
ter each use.
SLOW CHANGE OVERRIDE (MD09) — Slow change
override is in effect. The supply fluid temperature is close to
and moving towards the control point.
MINIMUM OFF TIME ACTIVE (MD10) — Unit is being
held off by Minutes Off Time (ConfigurationOPT2DELY).
TEMPERATURE RESET (MD14) — Temperature reset is
in effect. In this mode, unit is using temperature reset to adjust
supply fluid set point upward and is currently controlling to the
modified set point. The set point can be modified based on return fluid, outdoor-air-temperature, space temperature, or 4 to
20 mA signal.
DEMAND LIMITED (MD15) — Demand limit is in effect.
This indicates that the capacity of the unit is being limited by
®
) control. Override expires af-
demand limit control option. Because of this limitation, the unit
may not be able to produce the desired supply fluid temperature. Demand limit can be controlled by switch inputs or a 4 to
20 mA signal.
LOW TEMPERATURE COOLING (MD17) — Unit is in
Cooling mode and the rate of change of the supply fluid is negative and decreasing faster than -0.5° F per minute. Error between supply fluid and control point exceeds fixed amount.
Control will automatically unload the unit if necessary.
HIGH TEMPERATURE COOLING (MD18) — Unit is in
Cooling mode and the rate of change of the supply fluid is positive and increasing. Error between supply fluid and control
point exceeds fixed amount. Control will automatically load
the unit if necessary to better match the increasing load.
TIME GUARD ACTIVE (MDTG) — Compressor time
guard is active, preventing the compressor from starting.
HIGH SCT CIRCUIT A (MD21) — Unit is in a Cooling
mode and the saturated condensing temperature (SCT) is greater than the calculated maximum limit. No additional stages of
capacity will be added. Unit capacity may be reduced if SCT
continues to rise to avoid high-pressure switch trips by reducing condensing temperature.
HIGH SCT CIRCUIT B (MD22) — Unit is in a Cooling
mode and the saturated condensing temperature (SCT) is greater than the calculated maximum limit. No additional stages of
capacity will be added. Unit capacity may be reduced if SCT
continues to rise to avoid high-pressure switch trips by reducing condensing temperature.
MINIMUM COMP ON TIME (MD23) — Cooling load
may be satisfied, however control continues to operate compressor to ensure proper oil return. This may be an indication of
oversized application, low fluid flow rate or low loop volume.
LOW SOUND MODE (MD25) — Not applicable.
Operation of Machine Based on Control
Method —
the configuration of the control method
(ConfigurationOPT2CTRL). With the control method
set to 0, simply switching the Enable/Off/Remote Contact
switch to the Enable or Remote Contact position (external contacts closed) will put the unit in an occupied state. The control
mode (Operating ModesMODE) will be 1 (OFF LOCAL)
when the switch is Off and will be 5 (ON LOCAL) when in the
Enable position or Remote Contact position with external contacts closed.
Two other control methods are available for Machine On/
Off control:
OCCUPANCY SCHEDULE (CTRL=2) — The main base
board will use the operating schedules as defined under the
Time Clock mode in the scrolling marquee display. These
schedules are identical. The schedule number must be set to 1
for local schedule.
The schedule number can be set anywhere from 65 to 99
for operation under a CCN global schedule. The Enable/Off/
Remote Contact must be in the Enable or Remote Contact position. The control mode (Operating ModesMODE) will be 1
when the switch is Off. The control mode will be 3 when the
Enable/Off/Remote Contact switch input is On and the time of
day is during an unoccupied period. Similarly, the control
mode will be 7 when the time of day is during an occupied
period.
CCN SCHEDULE (CTRL=3) — An external CCN device
controls the On/Off state of the machine. This CCN device
forces the variable 'CHIL_S_S' between Start/Stop to control
the unit. The control mode (Operating ModesMODE) will
be 1 when the switch is Off. The control mode will be 2 when
the Enable/Off/Remote Contact switch input is On and the
Machine On/Off control is determined by
28
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