Armstrong Air 4SCU20LX User manual

1
August 2015
4SCU20LX
SERVICE MANUAL
ALLIED AIR
ENTERPRISES 4SHP20LX
This unit is an integral component of a communicating system
that requires a Comfort Sync™ thermostat and communicating
air handler or furnace.
IMPORTANT:
Before applying any power (main or low voltage) to the outdoor
unit, confirm the Comfort Sync™ thermostat has software
Version 2.13 or higher installed. (Reference the Comfort Sync™
thermostat manual.)
WARNING
Improper installation, adjustment, alteration, service or
maintenance can cause personal injury, loss of life, or
damage to property. Installation and service must be
performed by a licensed professional installer (or
equivalent) or a service agency.
TABLE OF CONTENTS
I. GENERAL
Electrical 1.....................................
II. SYSTEM OPERATION AND SERVICE
7-Segment Alert and System Status Codes 7.......
Outdoor Control Push-Button Operation 15..........
Configuring Unit 19...............................
Reconfiguring Outdoor Control using Comfort Sync™
Thermostat 20...................................
System Overview 20.............................
Maintenance 21..................................
Unit Sequence of Operations 23...................
Component Testing 26............................
System Refrigerant 45............................
Appendix - Wiring Diagrams ....................
IMPORTANT
The Clean Air Act of 1990 bans the intentional venting of
refrigerant (CFCs, HCFCs AND HFCs) as of July 1, 1992.
Approved methods of recovery, recycling or reclaiming
must be followed. Fines and/or incarceration may be
levied for noncompliance.
I. GENERAL
• Refer to the specification sheet for information regard
ing electrical ratings, sound ratings, performance
ratings, unit dimensions and other technical data.
• See Installation Instructions for unit installation and
charging procedures.
• See long line set guidelines for lines exceeding 50 ft.
(including risers) and maximum risers of 20 ft.
• Refer to Comfort Sync™ thermostat manual for opera
tion and programming of thermostat.
• Refer to indoor air handler/coil or furnace equipment
installation instructions for installation information.
• These instructions are intended as a general guide and
do not supersede local codes in any way. Consult au
thorities who have jurisdiction before installation.
The 20LX units are high-efficiency residential split-sys
tems which feature a variable-capacity scroll
compressor and use HFC-410A refrigerant. Units are
available in 2, 3, 4 and 5-ton sizes. These units are de
signed for use only with an expansion valve (approved
for use with HFC-410A) in the indoor unit.
WARNING
Electric Shock Hazard. Can cause injury or death. Unit
must be grounded in accordance with national and local
codes.
Line voltage is present at all components when unit is not
in operation on units with single‐pole contactors.
Disconnect all remote electric power supplies before
opening access panel. Unit may have multiple power
supplies.
WARNING
Electrical Hazard
High Voltage
Wait 5 Minutes
Electrical components may hold charge. Do
not remove this panel or service this area for
5 minutes after the power has been
removed.
Electrical
IMPORTANT
Connect line voltage power supply wiring to the outdoor
unit before connecting low voltage wiring from the main
outdoor unit control to the thermostat. Failure to follow
this may result in a communication error.
Wiring must conform with current local codes and the current
National Electric Code (NEC). In Canada, wiring must con
form with current local codes and the current Canadian
Electrical Code (CEC).
24VAC TRANSFORMER
Use the transformer provided with the furnace or air hand
ler for low‐voltage control power (24VAC - 40 VA
minimum).
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2
Load Shedding
Utility Load Shedding Mode ACTIVATED
(Utility Cycled Unit OFF) – The normally closed set of
contacts in the utility load shedding control receiver OPEN.
This removes 24VAC from the coil of the field-provided re
lay (catalog # 69J79). The relay contacts close (terminal 7
to terminal 2), completing the circuit between terminals R
and Lon the outdoor control. The 24VAC input to terminal L
activates the load shedding mode in the outdoor control,
cycling the outdoor unit OFF. The 7-Segment display on
the outdoor control displays a load shedding alert code
(E600) and an alert appears on the display of the Comfort
Sync™ thermostat. The customer receives email notifica
tions when the alert occurs, if the option to receive
notifications is selected.
Utility Load Shedding Mode DEACTIVATED
(Normal Equipment Operation) – When load shedding is
not required, the contacts in the utility load control receiver
are closed. This provides 24VAC to the coil of the field-
provided relay (catalog # 69J79).The relay contacts OPEN
(terminal 7 to terminal 2) removing 24VAC from the Lter
minal on the outdoor control. This deactivates the load
shedding mode in the outdoor control. The outdoor unit re
turns to normal operation and alert code clears once load
shedding mode is deactivated.
For more information, see the Load Shedding Feature on
page 22.
REFER TO THE UNIT NAMEPLATE FOR MINIMUM CIRCUIT AMPACITY,
AND MAXIMUM FUSE OR CIRCUIT BREAKER (HACR PER NEC).
INSTALL POWER WIRING AND PROPERLY SIZED DISCONNECT
SWITCH.
NOTE - UNITS ARE APPROVED FOR USE ONLY WITH COPPER
CONDUCTORS. GROUND UNIT AT DISCONNECT SWITCH OR TO AN
EARTH GROUND.
SIZE CIRCUIT AND INSTALL DISCONNECT
SWITCH
1
NOTE - 24VAC, CLASS II CIRCUIT CONNECTIONS ARE MADE IN THE CON
TROL BOX.
INSTALL ROOM THERMOSTAT (ORDERED SEPARATELY) ON AN
INSIDE WALL, APPROXIMATELY IN THE CENTER OF THE
CONDITIONED AREA AND 5 FEET (1.5M) FROM THE FLOOR. IT
SHOULD NOT BE INSTALLED ON AN OUTSIDE WALL OR WHERE IT
CAN BE AFFECTED BY SUNLIGHT OR DRAFTS.
THERMOSTAT
5 FEET
(1.5M)
INSTALL THERMOSTAT
2
DISCONNECT
SWITCH
MAIN FUSE BOX/
BREAKER PANEL
Figure 1. Electrical Installation Figure 2. Thermostat Location

3
ROUTE CONTROL WIRES
Maximum length of wiring (18 gauge) for all connections on the RSBus is 1500 feet (457 meters). Wires should be color-coded, with
a temperature rating of 95ºF (35ºC) minimum, and solid-core (Class II Rated Wiring). All low voltage wiring must enter unit through
field-provided field-installed grommet installed in electrical inlet.
The Comfort Sync™ thermostat requires four thermostat wires between the thermostat and the furnace / air handler control and four
wires between the outdoor unit and the furnace/air handler control. When a thermostat cable with more than four wires is used, the
extra wires must be properly connected to avoid electrical noise (see below).
Use a wire nut to bundle the four unused wires at each end of the cable. Each bundle should also include an additional wire that should
be connected on each end to the C terminal as shown in the figure below.
Any excess high voltage field wiring should be trimmed and secured away from any low voltage field wiring. To facilitate a conduit, a
cutout is located on the bottom of the control box. Connect conduit to the control box using a proper conduit fitting.
ROUTE HIGH VOLTAGE AND GROUND WIRES
Indoor Control
Single Wire To
C Terminal
Unused Wires
Unused Wires
Single Wire To C Terminal
OUTDOOR UNIT
PROVIDED RAST
6-PIN CONNECTOR
CONNECTS TO
RAST 6-PIN
CONNECTOR
ROUTE CONTROL
WIRING THROUGH
GROMMET AND
SECURE WITH
CABLE TIE
GROMMET AND
CABLE TIE.
USE WATERTIGHT
CONDUIT FOR HIGH
VOLTAGE
CONNECT CONDUIT
TO CUTOUT AND
ROUTE HIGH
VOLTAGE WIRING
INDOOR CONTROL
3
4
Figure 3. Electrical Installation (Continued)

4
CAUTION
ELECTROSTATIC DISCHARGE
(ESD)
Precautions and Procedures
Electrostatic discharge can affect electronic components. Take precautions
during unit installation and service to protect the unit's electronic controls.
Precautions will help to avoid control exposure to electrostatic discharge by
putting the unit, the control and the technician at the same electrostatic potential.
Neutralize electrostatic charge by touching hand and all tools on an unpainted
unit surface before performing any service procedure.
STEP 3 -- ELECTRICAL (Continued) -- Outdoor Control Unit
PUSH
BUTTON
7-SEGMENT
DISPLAY
PUMP DOWN - WHEN THE UNIT IS IN PUMP DOWN MODE,  IS
SHOWN ON THE 7-SEGMENT DISPLAY.
TO ACTIVATE PUMP DOWN MODE, REFER TO PUMP DOWN
CYCLE SEQUENCE ON PAGE 16.
NOTE - The green LED located on the outdoor control flashes
when communication occurs between the outdoor control and
either the thermostat or the inverter.
Figure 4. Outdoor Control Unit

5
TABLE 1
Outdoor Control Terminal Designations and Input /Outputs (see figure 4 for terminal locations)
Designator Description Input Output Common
OFor heat pump applications only. N/A Switched 24VAC
nominal N/A
O OUT For heat pump applications only. N/A N/A 24VAC common
LO PS Low pressure switch N/A 5ma @18VAC N/A
LO PS Low pressure switch sensing connection 5ma @18VAC N/A N/A
Hi PS High pressure switch N/A 24VAC nominal N/A
Hi PS High pressure switch sensing connection 24VAC nominal N/A N/A
TP Top cap thermostat switch (in series with the HI
PS) N/A 24VAC nominal N/A
TP Top cap thermostat switch sensing connection 24VAC nominal N/A N/A
Cntctr Control (inverter power) contactor switched out
put (in series with the HI PS and TC) N/A Switched 24VAC Nominal N/A
Cntctr Contactor common N/A 24VAC common
Fan PWM PWM fan output N/A 1097% duty cycle,
1923 VDC peak N/A
COM PWM fan common connection N/A N/A Fan PWM com
mon
Fan Park PWM fan parking spot for unused terminal, not
connected. N/A N/A N/A
P2 Terminal Designations (Outdoor Board)
OFor heat pump applications only.
24VAC nominal from ther
mostat and loaded to draw
17ma at 30VAC
N/A N/A
Y1 Y1 emergency input
24VAC nominal from ther
mostat and loaded to draw
17ma at 30VAC
N/A N/A
C24VAC nominal power return. N/A N/A 24VAC common
i Low data line. Data Data N/A
i+ High data line. Data Data N/A
R24VAC nominal power input. 24VAC nominal board main
power input. N/A N/A
DF OEM test N/A N/A N/A
TOUT 26Vdc transistor output to factory tester N/A N/A N/A
TST
OEM test pin.
In each terminal box:
P2  Terminal 1  TEST
P2  Terminal 2  TOUT
P2  Terminal 3  DF
P2  Terminal 4  R
24VAC nominal 17ma @
30VAC N/A N/A

6
Table 1 continued.
Outdoor Control Terminal Designations and Input /Outputs
WARNING - Electric Shock Hazard. Can cause injury or death. Unit must be grounded in accordance with national and
local codes. The 4 pins in P6 have the potential of transferring up to 250 volts to the unit cabinet ground.
Designator Description (Outdoor Board) Input Output Common
P6 - Pin 1 Tx Transmit data to inverter, connects to
Rx of inverter.
Outdoor control
communication
transmit pin.
• Pin 1 to pin 2 should read 4.5 to 5.5
VDC when not communicating.
• Pin 3 to pin 2 should read 4.5 to 5.5
VDC when not communicating.
• Pin 4 to pin 2 should read 4.5 to 5.5
VDC.
NOTE - Communication signals switch off
and on rapidly. This may cause volt meter
readings to fluctuate. This is normal.
Communication signals will switch
between this 5V and common (Pin 2).
P6 - Pin 2 Inverter
Common
Inverter common
NOTE - This is a signal reference point
and not an earth ground.
Inverter common.
P6 - Pin 3 Rx Receive data from the inverter.
Connects to Tx of inverter.
Outdoor control
communication
receive pin.
P6 - Pin 4 Inv 5V Inverter 5VDC volts. Inverter 5VDC volts
LIQ Liquid line temperature sensor sup
ply. N/A N/A N/A
LIQ Liquid line temperature sensor return. N/A N/A N/A
AMB Outdoor ambient temperature sensor
supply. N/A N/A N/A
AMB Outdoor ambient temperature sensor
return. N/A N/A N/A
COIL Outdoor coil temperature sensor sup
ply. N/A N/A N/A
COIL Outdoor coil temperature sensor re
turn. N/A N/A N/A
Pump Down
To initiate pump down function, place jumper
in the ON position. (See PUMP DOWN MODE
OPERATION.)
1. Place the jumper in the ON position to
activate pump down mode.
2. Place the jumper in the OFF position to
deactivate pump down mode.
NOTE -If the pump down jumper is in the ON
position during power-up, it is ignored.
NOTE - The outdoor control stays in pump down
mode for five minutes, after which the outdoor
control initiates a compressor shutdown
sequence.
PUMP
DOWN PUMP
DOWN
ON
OFF
ON
OFF
LLoad shedding input
24VAC input to Len
ergizes load shed
ding feature.
N/A N/A
C
Load shedding input reference. Refer
to wiring of load shedding terminals
located on page 22.
N/A N/A 24VAC
common

7
II. SYSTEM OPERATION AND SERVICE
Connect line voltage power supply wiring to the outdoor unit before connecting low voltage wiring from the
main outdoor unit control to the thermostat. Failure to follow this may result in a communication error.
7-Segment Alert and System Status Codes
Alert codes are displayed using the 7-segment display loc
ated on the outdoor control.
NOTE - System fault and lockout codes take precedence
over system status codes (cooling, heating operating per
centages or defrost/dehumidification).
The 7-segment will display an abnormal condition (error
code) when detected in the system. A list of the codes are
shown in table 2.
RESETTING ALERT CODES
Alert codes can be reset manually or automatically:
1. Manual Reset
Manual reset can be achieved by one of the following
methods:
•Disconnecting R wire from the outdoor control R
terminal.
•Turning the indoor unit off and back on again
After power up, all currently displayed codes are
cleared.
2. Automatic Reset
After an alert is detected, the outdoor control continues
to monitor the unit's system and compressor opera
tions. When/if conditions return to normal, the alert
code is turned off automatically.
NOTE - Error codes can be recalled by following in
formation shown in table 3.
Table 2. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes
NOTE - System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/dehumidification).
Only the latest active fault or lockout codes are displayed (if present). If no fault or lockout codes are active, then system status codes are displayed. Alert
codes are also displayed on the Wi-Fi®thermostat.
Alert
Codes
Inverter
Code
Inverter LED Flash
Code (number of
flashes) Priority Alarm Description Possible Causes and Clearing Alarm
Red LED Green LED
N/A N/A ON OFF N/A -024 and -036 only: Indicates inverter is operating normally.
N/A N/A ON ON N/A -048 and -060 only: Indicates inverter is operating normally.
N/A N/A OFF OFF N/A Indicates inverter is NOT energized.
E 105 N/A N/A N/A Moderate
The outdoor control has
lost communication with
either the thermostat or in
door unit.
Equipment is unable to communicate. Indicates numer
ous message errors. In most cases errors are related to
electrical noise. Make sure high voltage power is separ
ated from RSBus. Check for miswired and/or loose con
nections between the stat, indoor unit and outdoor unit.
Check for a high voltage source of noise close to the sys
tem. Fault clears after communication is restored.
E 120 N/A N/A N/A Moderate
There is a delay in the out
door unit responding to the
system.
Typically, this alarm/code does not cause any issues
and clears on its own. The alarm/code is usually
caused by a delay in the outdoor unit responding to the
thermostat. Check all wiring connections. Cleared
after unresponsive device responds to any inquiry.
E 124 N/A N/A N/A Critical
The Wi-Fi®thermostat has
lost communication with the
outdoor unit for more than 3
minutes.
Equipment lost communication with the thermostat.
Check the wiring connections and resistance, then
cycle the system power. This alarm stops all associ
ated HVAC operations and waits for a signal from the
non-communicating unit. The alarm / fault clears after
communication is reestablished.
E 125 N/A N/A N/A Critical
There is a hardware prob
lem with the outdoor con
trol.
There is a control hardware problem. Replace the out
door control if the problem prevents operation and is
persistent. The alarm / fault is cleared 300 seconds after
the fault recovers.
E 131 N/A N/A N/A Critical The outdoor unit control
parameters are corrupted.
Reconfigure the system. Replace the control if heating or
cooling is not available.
E 132 N/A N/A N/A Critical Internal software error. Replace outdoor control.
E 180 N/A N/A N/A Critical
The outdoor unit ambient
temperature sensor has
malfunctioned. As a result
the outdoor unit control will
not perform low ambient
cooling.
Valid temperature reading is lost during normal opera
tion and after outdoor control recognized sensors.
Compare outdoor sensor resistance to temperature/
resistance charts in unit installation instructions. Re
place sensor pack if necessary. At the beginning of
(any) configuration, furnace or airhandler control de
tects the presence of the sensor(s). If detected (reading
in range), appropriate feature is shown in the thermostat
About screen. The alarm / fault clears upon configura
tion, or when normal values are sensed.

8
Table 2. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes
NOTE - System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/dehumidification).
Only the latest active fault or lockout codes are displayed (if present). If no fault or lockout codes are active, then system status codes are displayed. Alert
codes are also displayed on the Wi-Fi®thermostat.
Alert
Codes
Inverter
Code
Inverter LED Flash
Code (number of
flashes) Priority Alarm Description Possible Causes and Clearing Alarm
Red LED Green LED
E 345 N/A N/A N/A Critical
Heat Pump or Air Conditioner
Alert Code - The "O" relay on
the outdoor board has failed.
Either the pilot relay contacts
did not close, the relay coil
did not energize or the circuit
that confirms this operational
sequence is not sensing
properly.
Issue: Broken R50 will make the control board think re
versing valve output is always off regardless of state of re
lay. (Supplier issue - We have found our functional test fix
ture can bend over MOV2 and crush it into R50.There are
cut-outs in the plate of the fixture to let the two relays pass
through as the plate with pogo pins is moved to the board
to make contact with the terminals.
Corrective Actions: Short term fix: Converted the sys
tem back to a 24 volt system to get unit operating. Long
term: Replace outdoor control.
E 409 N/A N/A N/A Moderate Outdoor control secondary
voltage is 18VAC or less.
Secondary voltage is below 18VAC. After 10 minutes, op
eration is discontinued. Check the indoor line voltage and
transformer output voltage. The alarm clears after the
voltage is higher than 20VAC for 2 seconds or after a
power reset.
E 410 N/A N/A N/A Moderate
The outdoor unit cycled off
due to low pressure switch
opening.
Unit pressure is below the lower limit. The system is shut
down. The low pressure switch closes above 90PSIG and
opens below 40PSIG. Confirm that the system is properly
charged with refrigerant. Check TXV, indoor unit blower
motor, dirty filters or clogged refrigerant filter. Confirm that
the evaporator coil is clean. The alarm clears after the
pressure switch opens or after a power reset.
E 411 N/A N/A N/A Critical
The low pressure switch has
opened 5 times within one
hour. As a result, the outdoor
unit is locked out.
Low pressure switch error count reached 5 strikes. The
low pressure switch opens at 40PSIG and resets at
90PSIG. Confirm that the system is properly charged with
refrigerant. Check for clogged TXV, blockage to indoor
unit blower motor, dirty filters or clogged refrigerant filter.
Confirm that the evaporator coil is clean. The alarm clears
after a power reset.
E 412 N/A N/A N/A Moderate The outdoor unit high pres
sure switch has opened.
Unit pressure is above the upper limit. System is shut
down. The high pressure switch opens at 590PSIG and
closes at 418PSIG. Confirm that the system is properly
charged with refrigerant. Check for clogged TXV, block
age to indoor unit blower motor, clogged refrigerant filter.
Confirm that the outdoor unit is clean. The alarm clears
after the pressure switch closes or a power reset.
For heating, indoor CFM may be set too low. For zoning
system, zone CFM may be set too low.
E 413 N/A N/A N/A Critical
The high pressure switch has
opened 5 times within one
hour. As a result, the outdoor
unit is locked out.
Open high pressure switch error count reached 5 strikes.
System is shut down. The high pressure switch for
HFC410A opens at 590PSIG and closes at 418PSIG.
Confirm that the system is properly charged with refriger
ant. Check condenser fan motor, for clogged TXV, for
blockage to indoor unit blower motor, for stuck reversing
valve or clogged refrigerant filter. Confirm that the out
door unit is clean. The alarm clears after a power reset.
For heating, indoor CFM may be set too low. For zoning
system, zone CFM may be set too low.
E 416 N/A N/A N/A Moderate
/ Critical
The outdoor coil sensor has
malfunctioned. As a result
the outdoor unit control will
not perform defrost.
Coil sensor being detected open or shorted, or temperat
ure is out of coil sensor range. Outdoor unit control will not
perform demand or time/temperature defrost operation.
System is still able heat and cool. Check the resistance of
the coil sensor and compare to temperature resistance
chart. Replace coil sensor if needed. The alarm clears
when outdoor unit control detects proper coil sensor
readings or after a power reset.

9
Table 2. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes
NOTE - System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/dehumidification).
Only the latest active fault or lockout codes are displayed (if present). If no fault or lockout codes are active, then system status codes are displayed. Alert
codes are also displayed on the Wi-Fi®thermostat.
Alert
Codes
Inverter
Code
Inverter LED Flash
Code (number of
flashes) Priority Alarm Description Possible Causes and Clearing Alarm
Red LED Green LED
E 422 N/A N/A N/A Moderate Compressor top cap switch
exceeding thermal limit.
Issue: One of the wires from the top cap switch had pulled
off one of the TP terminals on the outdoor control board.
Corrective Action: Reconnected wire onto top cap ter
minal.
E 423 40 4 flashes OFF Moderate /
Critical
The inverter has detected a
circuit problem.
Control locks out after 10 strikes within an hour. To clear,
disconnect power to outdoor unit and restart.
E 424 N/A N/A N/A Moderate The liquid line temperature
sensor has malfunctioned.
In normal operation, after outdoor control recognizes
sensors, the alarm is sent if valid temperature reading is
lost. Compare liquid line sensor resistance to temperat
ure/resistance charts in unit installation instructions. Re
place sensor pack if necessary. At the beginning of (any)
configuration, furnace or airhandler control detects the
presence of the sensor(s). If detected (reading in range),
appropriate feature is shown in the thermostat About
screen. The alarm / fault clears upon configuration, or
when normal values are sensed.
E 425 N/A N/A N/A Minor
Outdoor control has in
creased minimum com
pressor speed to allow for
proper oil return due to low
ambient temperature. NOTE -
Minimum speed adjustments
begin at 45°F and increase to
100% minimum at 17°F.
Outdoor ambient temperature is below system limit. Con
trol attempts to run at lowest allowed compressor speed
to allow for proper oil return. Automatically clears when
outdoor ambient temperature rises above limit for more
than 5 minutes.
E 426 N/A N/A N/A Critical Excessive inverter alarms
After ten faults within one hour, control is locked out, indic
ating poor system operation. Review history of alarms to
resolve system setup. Check condenser fan motor, TXV,
indoor unit blower motor, over-charge, undercharge, or
clogged refrigerant filter.
To clear error, disconnect power to outdoor unit and re
start. Inverter alarms 12 to 14 and 53 do not count toward
this lock out condition.
E 427 21 2 flashes 1 flash Moderate /
Critical
The inverter has detected a DC peak fault condition. If condition (55A or higher) is detec
ted, outdoor unit compressor and fan stop. Anti-short cycle is initiated. If peak current
(55A or higher) occurs 10 times within an hour, system is locked out. Indicates high pres
sure, condenser fan failure, locked compressor rotor or overcharge. To clear, disconnect
power to outdoor unit and restart.
E 428 22 2 flashes 2 flashes Moderate /
Critical
The inverter has detected a
high main input current con
dition.
If condition is detected, is detected, outdoor unit com
pressor and fan stop. Antishort cycle is initiated. If condi
tion occurs 5 times within an hour, system is locked out.
Indicates high pressure, condenser fan failure or over
charge.
To clear, disconnect power to outdoor unit and restart.
E 429 23 2 flashes 3 flashes Moderate /
Critical
On a call for compressor op
eration, if DC link power in in
verter does not rise above
180 VDC for 2 and 3 ton mod
els, 250 VDC for 4 and 5 ton
models, within 30 seconds,
the control will display a mod
erate code. If condition is de
tected, outdoor unit will stop
(Compressor and fan). Anti-
short cycles is initiated. If
condition occurs 10 times
within a 60 minute rolling time
period, system will lock out
and display a critical code.
Issues:
(1) If DC link power in inverter does not rise above 180
VDC for 2- and 3-ton models, 250 VDC for 4- and 5-ton
models, within 30 seconds, the outdoor control will dis
play a moderate code.
(2) Capacitors on inverter do not properly charge.
Corrective Actions:
(1) check for proper main power to outdoor unit and for
any loose electrical connections.
(2) Outdoor control boards with part # 103686-03 have
software update to delay the de-energizing of the revers
ing valve by four seconds when coming out of defrost.

10
Table 2. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes
NOTE - System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/dehumidification).
Only the latest active fault or lockout codes are displayed (if present). If no fault or lockout codes are active, then system status codes are displayed. Alert
codes are also displayed on the Wi-Fi®thermostat.
Alert
Codes
Inverter
Code
Inverter LED Flash
Code (number of
flashes) Priority Alarm Description Possible Causes and Clearing Alarm
Red LED Green LED
E 430 26 2 flashes 6 flashes Moderate /
Critical Compressor start failure.
If condition is detected, outdoor unit compressor and fan
stop. Antishort cycle is initiated. If condition occurs 10
times within an hour, system is locked out.
Indicates poor connection at compressor harness, im
proper winding resistance, locked compressor rotor, or
flooded compressor.
To clear, disconnect power to outdoor unit and restart.
E 431 27 2 flashes 7 flashes Moderate /
Critical
Error occurs when PFC de
tects an over-current condi
tion of 100A, the control will
display a moderate code. If
condition is detected, out
door unit will stop (Com
pressor and fan). Anti-short
cycle is initiated. Inverter is
unavailable to communicate
with the outdoor control for 3
minutes. If condition occurs
10 times within a 60 minute
rolling time period, system
will lock out and display a crit
ical code.
Issues:
(1) Indicates power interruption, brownout, poor electrical
connection or loose inverter input wire.
(2) System testing was set up and code was generated
when the reversing valve is de-energized coming out of
defrost (code appears with or without 30 compressor
delay).
Corrective Actions:
(1) Check for proper main power to outdoor unit and for
any loose electrical connections.
(2) Outdoor control boards with part # 103686-03 have
software update to delay the de-energizing of the revers
ing valve by four seconds when coming out of defrost.
E 432 28 2 flashes 8 flashes Moderate
/ Critical
The inverter has detected a
DC link high voltage condi
tion.
Error occurs when the DC link capacitor voltage is greater
than 480VDC. If condition is detected, outdoor unit com
pressor and fan stop. Antishort cycle is initiated. If condi
tion occurs 10 times within an hour, system is locked out.
System stops. To clear, disconnect power to outdoor unit
and restart.
E 433 29 2 flashes 9 flashes Moderate
/ Critical
The inverter has detected a
compressor over-current
condition.
Error occurs when compressor peak phase current is
greater than 28A. Inverter issues code 14 first and slows
down to try to reduce the current. If the current remains
high, outdoor unit compressor and fan stop. Antishort
cycle is initiated. If condition occurs five times within an
hour, system is locked out. To clear disconnect power to
outdoor unit and restart.
E 434 53 5 flashes 3 flashes Moderate /
Critical
Outdoor control has lost
communications with the
inverter for greater than 3
minutes. Outdoor control
will stop all compressor de
mands, recycle power to
the inverter by de-energiz
ing the contactor for 2
minutes. If this occurs 3
time in one thermostat call,
the outdoor unit will locked
out and display a critical
code.
Issues:
(1) Loose electrical connections.
(2) Interruption of main power to inverter.
Corrective Actions:
(1) Check all electrical connections.
(2) Check for proper main power to inverter.
E 435 60 6 flashes OFF Moderate /
Critical Inverter internal error.
When this error occurs, the outdoor control cycles power
to the inverter by opening the contactor for two minutes.
Check that the EEPROM is properly seated. After power
is cycled to the inverter 3 times, the outdoor unit is locked
out.

11
Table 2. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes
NOTE - System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/dehumidification).
Only the latest active fault or lockout codes are displayed (if present). If no fault or lockout codes are active, then system status codes are displayed. Alert
codes are also displayed on the Wi-Fi®thermostat.
Alert
Codes
Inverter
Code
Inverter LED Flash
Code (number of
flashes) Priority Alarm Description Possible Causes and Clearing Alarm
Red LED Green LED
E 436 62 6 flashes 2 flashes Moderate /
Critical
Inverter heat sink temperat
ure exceeded limit. Occurs
when the heat sink temper
ature exceeds the inverter
limit. Inverter issues code
13 first, then slows down to
allow the heat sink to cool. If
temperature remains high,
outdoor unit stops (com
pressor and fan). Anti-short
cycle is initiated. If condition
occurs 5 times within an
hour, system is locked out.
To clear, disconnect power
to outdoor unit and restart.
Issue: Feedback from supplier tear down of inverter in
dicates that the screws that hold the inverter to the invert
er board were loose causing poor contact between these
two components.
Corrective Action: Tighten screws that hold the heat
sink to the inverter control board.
NOTE: Wait five minutes to all capacitor to discharge be
fore checking screws.
E 437 65 6 flashes 5 flashes Moderate /
Critical
Heat sink temperature
sensor fault has occurred
(temperature less than 4ºF
or greater than 264ºF after
10 minutes of operation).
Occurs when the temperature sensor detects a temperat
ure less than 0.4ºF or greater than 264ºF after 10 minutes
of operation. If condition is detected, outdoor unit will stop
(compressor and fan). Antishort cycle is initiated. If con
dition occurs 5 times within an hour, system will lock out.
To clear disconnect power to outdoor unit and restart. If
problem persists, replace inverter.
E 438 73 7 flashes 3 flashes Moderate /
Critical
The inverter has detected a
PFC over current condition.
This would be caused by a
high load condition, high
pressure, or outdoor fan fail
ure.Outdoor control will dis
play the code when the in
verter has the error. After 3
minutes, the inverter will re
set and the compressor will
turn on again. If it happens
10 times within a 60 minute
rolling time period, the OD
control will lock out opera
tion of the outdoor unit and
display a critical code.
Issue: Possible issue is system running at high pres
sures. Check for high pressure trips or other alert codes in
room thermostat and outdoor control.
E 439 12 1 flash 2 flashes Moderate Compressor slowdown due
to high input current.
Input current is approaching a high limit. Compressor
speed automatically slows. The control continues send
ing the inverter speed demanded by the thermostat. The
control sets indoor CFM and outdoor RPM to values ac
cording to demand percentage rather than the actual Hz.
Alarm is automatically cleared.
E 440 13 1 flash 3 flashes Moderate
Heat sink temperature is
approaching limit. The
compressor speed auto
matically slows to reduce
heat sink temperature. The
control sets indoor CFM
and outdoor RPM to values
according to demand per
centage rather than the ac
tual Hz. Alarm is automatic
ally cleared.
Issue: Feedback from supplier tear down of inverter in
dicates that the screws that hold the inverter to the invert
er board were loose causing poor contact between these
two components.
Corrective action: Tighten screws that hold the heat sink
to the inverter control board.
NOTE: Wait 5 minutes to all capacitor to discharge before
checking screws.

12
Table 2. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes
NOTE - System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/dehumidification).
Only the latest active fault or lockout codes are displayed (if present). If no fault or lockout codes are active, then system status codes are displayed. Alert
codes are also displayed on the Wi-Fi®thermostat.
Alert
Codes
Inverter
Code
Inverter LED Flash
Code (number of
flashes) Priority Alarm Description Possible Causes and Clearing Alarm
Red LED Green LED
E 441 14 1 flash 4 flashes Moderate
Compressor slowdown due
to high compressor current.
Compressor current is ap
proaching limit. The com
pressor speed automatic
ally slows. The control sets
indoor CFM and outdoor
RPM to values according to
demand percentage rather
than the actual Hz. Alarm is
automatically cleared..
Issue: Possible issue is system running at high pres
sures. Check for high pressure trips or other alert codes in
room thermostat and outdoor control.
E 442 N/A N/A N/A Critical
The top cap switch has
opened five times within
one hour. As a result, the
outdoor unit is locked out.
When compressor thermal protection sensor opens five
times within one hour, outdoor stops working. To clear,
disconnect power to outdoor unit and restart.
E 443 N/A N/A N/A Critical Incorrect appliance unit
size code selected.
Check for proper configuring of unit size codes for out
door unit in configuration guide or in installation instruc
tions. If replacing inverter, verify inverter model matches
unit size. The alarm/fault clears after the correct match is
detected following a reset. Remove the thermostat from
the system while applying power and reprogramming.
E 600 N/A N/A N/A Critical
Compressor has been
cycled OFF on utility load
shedding.
Load shedding function: Provides a method for a local
utility company to limit the maximum power level usage of
the outdoor unit. The feature is activated by applying 24
volts AC power to the L and C terminals on the outdoor
control.
E 601 N/A N/A N/A Critical
Outdoor unit has been
cycled OFF on low temper
ature protection.
Low temperature protection: Outdoor unit will not operate
when the outdoor temperature is at or below 4°F
(20°C). If the unit is operating and the outdoor temper
ature drops below 4°F (20°C), the unit continues to op
erate until the room thermostat is satisfied or the outdoor
temperature drops to 15°F (26°C). Outdoor unit ambi
ent sensor provides temperature readings.

13
UNIT TYPE: The next item displayed is the self discovery
unit type. AC = air conditioner and HP = heat pump. If the
unit type cannot be determined, three bars appear.
POWER-UP / RESET:
FIRMWARE VERSION: During initial power-up or reset, the
first item displayed is the outdoor control firmware version.
Example to the right shows firmware version 2.3.

7-SEGMENT POWER-UP DISPLAY STRING

OR OR
UNIT CODE: The next item to be displayed is the self discov
ery unit code. (may be a single character or two characters).
If the unit code cannot be determined, three bars appear.

THROUGH OR
(These are just examples of firmware version, unit type,
unit nominal capacity and unit codes.)
UNIT CODE UNIT TYPE, SIZE AND MODEL







NOT PROGRAMMED
2-TON HEAT PUMP
3-TON HEAT PUMP
4-TON HEAT PUMP
5-TON HEAT PUMP
2-TON AIR CONDITIONER
3-TON AIR CONDITIONER
4-TON AIR CONDITIONER
5-TON AIR CONDITIONER
UNIT NOMINAL CAPACITY: The next item to be displayed
is the self-discovery unit nominal capacity. Valid capacities
are 24 for 2-ton, 36 for 3-ton, 48 for 4-ton and 60 for 5-ton
units. If the unit type cannot be determined, three bars ap
pear.

OR


7-SEGMENT POWER-UP DISPLAY STRING EXAMPLE
FIRMWARE
VERSION
UNIT
TYPE
UNIT
CAPACITY
UNIT
CODE
.
IDLE MODE
.
.








Figure 5. Outdoor Control 7-Segment Unit Status Displays

14
Table 3. Outdoor Control 7-Segment Unit Status Displays
Description Example of Display
Idle Mode: Decimal point flashes at 1 Hz. Idle Mode: Decimal point flashes at 1 Hz (0.5 second on, 0.5 second off).
Display OFF.
Soft Disable Mode: Top and bottom horizontal line and decimal
point flash at 1 Hz.
If indoor or outdoor control displays Soft Disable code:
1) Confirm proper wiring between all devices (thermostat, indoor
and outdoor).
2) Cycle power to the control that is displaying the Soft Disable
code.
3) Put the room thermostat through Setup.
4) Go to Setup/System Devices/Thermostat/Edit/push Reset.
5) Go to Setup/System Devices/Thermostat/Edit/push Reset All.
If the room thermostat detects a new device or a device that is
not communicating, it sends a Soft Disable. When this occurs,
Alarm 10 is activated and the room thermostat sends a Soft Dis
able command to the offending device on the bus (outdoor con
trol, IFC, AHC, EIM or Damper Control Module).
Soft Disable Mode: Top and bottom horizontal line and decimal point flash
at 1 Hz (0.5 second on, 0.5 second off).
The thermostat control in Soft Disable Mode is indicated by the following:
• On AHC, IFC and outdoor controls, Soft Disable Mode is indicated by
flashing double horizontal lines on the 7-segment display.
• On the Damper Control Module and EIM, the green LED will blink 3 sec
onds on and 1 second off.
O.E.M. Test Mode All segments flashing at 2 Hz (unless error is detected). NOTE - Control
should be replaced.
Anti-Short Cycle Delay
The middle line flashes at 1 Hz for 2 seconds, followed by a 2-second dis
play of the number of minutes left on the timer (value is rounded up: 2 min.
1 sec. is displayed as 3). If activated, the anti-short cycle delay time remain
ing is displayed (default is 300 sec./5 min.).
Cooling Cycle: Shows current percentage of maximum cooling
capacity. Example to the right indicates a cooling demand of 50
percent and a outdoor fan speed of 700 RPM.
The demand percentage is displayed first, followed by a pause, then the
outdoor fan speed and the ambient temperature.
   pause     pause   
Diagnostic recall: Shows the last 10 stored diagnostic error
codes.
If first error is    , second     pause     pause
   
Next codes (up to 10) are shown using same method.
Fault memory clears
If there are no error codes stored: pause    . After the fault memory
is cleared, the following string flashes every 0.5 seconds:
    pause
Active error in outdoor control Idle mode: Show all active
error(s) codes.
Following display string is repeated if Error E 125 and E 201 are present:
    pause    
Active error in run mode: Show current status and all active
error(s) codes.
Following display string is repeated if Error E 440 is present while outdoor
fan speed at 700RPM:
    pause    
Outdoor Ambient Temperature (OAT): Any time OAT is within
operating range, value is displayed if unit is in diagnostic and
non-diagnostic modes.
Following display string is repeated if cooling is active with outdoor fan
speed set at 650 RPM and OAT is 104ºF:
   pause     pause     pause
Outdoor Coil Temperature (OCT): Any time OCT is sensed in
operating range, value is displayed if unit is in diagnostic mode
or manually enabled for non-diagnostic modes.
Following display string is repeated if heat is active with outdoor fan speed
set at 550 RPM and OCT is 25ºF:
   pause     pause    pause
Liquid Line Temperature (LIQ): Any time LIQ is sensed in oper
ating range, value is displayed if unit is in diagnostic mode or
manually enabled for non-diagnostic modes.
Following display string is repeated if cooling is active with outdoor fan
speed set at 650 RPM and LIQ is 105ºF:
   pause     pause     pause
Pump Down Mode:While the unit is in pump down mode,  
is displayed repeatedly. Errors are shown if they exist.
Following display string is repeated:
  pause  
  pause     pause   pause    

15
PUSH −BUTTON OPERATION
_
_

Allows field access to Diagnostic, Fan, Defrost and Error Code
Recall modes.
Outdoor control must be in
IDLE mode (no heating or
cooling operation).
To enter mode options, push and hold button next to 7seg
ment display until DASH symbol appears. Immediately re
lease the button. Once dash starts flashing, proceed to
next step.
Push and hold button until mode
selection displays on the 7seg
ment display (, ,    , or
). Immediately release the button,
proceed to next step.
Push and hold button until the selection stops flashing, then release button. The 7 seg
ment display shows the selected mode and the control performs the selected function. 
NOTE - See table 2 for explanation of codes.
Figure 6. Push-Button Operation
Unit Selection Code for Outdoor Control
If the single-character display shows three (3) horizontal lines, the unit selection code needs to be programmed. Press and hold the button until the  
menu option is displayed, release button. The singlecharacter display displays the selected mode per example in figure 5. When the desired unit selec
tion code appears, press and hold the button until it stops flashing, then release.
Unit Code Unit Type Unit Model
 2-ton air conditioner 4SCU20LX124
 3-ton air conditioner 4SCU20LX136
 4-ton air conditioner 4SCU20LX148
 5-ton air conditioner 4SCU20LX160
 2-ton heat pump 4SHP20LX124
 3-ton heat pump 4SHP20LX136
 4-ton heat pump 4SHP20LX148
 5-ton heat pump 4SHP20LX160
2-ton air handler BCE4M245
2.5-ton air handler BCE4M305
3-ton air handler BCE4M365
4-ton air handler BCE4M485
5-ton air handler BCE4M605

16
Idle mode — System is energized with no demand — Decimal flashes at 1 Hertz > 0.5 second ON, 0.5 second OFF.
Display
Symbol or
Character
Display Fan Test and Display String Option
Displayed
during start-up
or power
recycling.
Display string shows outdoor control firmware version    > pause>   or   unit >pause>unit capacity in BTUs>pause >unit code. If 3
horizontal bars are displayed during any sequence of this display string, it indicates that the specific parameter is not configured.
.Idle mode — decimal flashes at 1 Hertz > 0.5 second ON, 0.5 second OFF
or Indicates either cooling () or heating () mode and demand percentage.
  Code displays when system is in defrost mode. To enter defrost mode, unit must be running in heating mode, outdoor ambient must
be below 65F and outdoor coil temperature must be below defrost termination temperature.
Indicates outdoor fan RPM speed.
Control must be in Idle mode: To enter fan test option - mode, push and hold button
until solid – appears, release button. Display begins flashing. Within 10 seconds, push and
hold button until required symbol displays, release button. Display begins flashing. With
in 10 seconds, push and hold button until display stops flashing, release button. Control
outputs DC voltage on PWM and COM terminals. Outdoor fan cycles ON for 10 minutes at
490 RPM. To exit test – Push and hold button until three horizontal bars display. Release
button, outdoor fan cycles OFF.

in the display string represents the
ambient temperature in F at the
sensor on the outdoor unit. In display
configuration mode, it also repres
ents the option for enabling both coil
and liquid line temperature on the
7-segment display string.
Control can be in Idle or demand mode: To enter display configuration option - mode, push
and hold button until solid – appears, release button. Display begins flashing. Within 10 sec
onds, push and hold button until required symbol displays, release button. Display begins
flashing. Within 10 seconds, push and hold button until display stops flashing, release button.
Display shows error () code(s), ambient (), outdoor coil () and liquid () temperatures in
Fahrenheit.
NOTE - If button is not pushed in the 10-second time period, the control exits the test mode. If
this occurs, test mode must be repeated.
Error Code Recall Mode (NOTE - control must be in idle mode)
To enter error code recall mode, push and hold button until solid appears, then release button. Control displays up to 10 error codes stored
in memory. If     is displayed, there are no stored error codes.
—
—
—
To exit error code recall mode, push and hold button until solid three horizontal bars appear, then release button. Note - Error codes are not
cleared.
To clear error codes stored in memory, continue to hold button while the 3 horizontal bars are displayed. Release button when solid is
displayed.
Push and hold for one (1) second, release button. 7-Segment displays
    and exits error recall mode.
FIELD TEST MODE OPERATION
The field test mode allows the unit to be put into diagnostic
mode and allows the installer to perform multiple tests on
the control / unit.
Diagnostic Mode
Diagnostic mode is only available when the system is idle
or during an active / suspended call for heating or cooling.
Diagnostic mode is terminated when the exit command is
given, the button is pressed and released without entering
the diagnostic menu or 10 minutes has passed, whichever
comes first.
When this mode is selected all installed temperature
sensor valves (non-open and non-short) are shown on the
7-segment display. The following system status codes are
displayed:
DCooling
DPercentage demand operation
DOutdoor fan RPM
DActive error codes
Outdoor Fan Mode
Diagnostic mode is only available while the system is in idle
mode. This mode can be exited with the proper command
or after 10 minutes has passed.
In diagnostic mode, the control ,energizes the outdoor fan
at the highest speed. The control continuously displays the
fan RPM on the 7-segment display.
PUMP DOWN MODE OPERATION
1. Turn room thermostat OFF.
2. Install a set of refrigerant gauges on the system to
monitor the pressure.
NOTE - All operation monitoring devices: High pressure
switch, low pressure switch and compressor internal vacu
um protection remain active in the system. This will prevent
the compressor from recovering all the system refrigerant
into the outdoor unit.
NOTE - If the pump down jumper is in the ON position dur
ing power-up, it is ignored.
3. Move the Pump Down jumper (figure 4) from the OFF
position to the ON position.

17
PUMP DOWN PUMP DOWN
ON
OFF
ON
OFF
Figure 7. Pump Down Jumper
4. Shut off the liquid line service valve to stop the flow of
refrigerant into the indoor coil.
5. After a three-second delay, the compressor and out
door fan will ramp up to 100% capacity. (Indoor fan will
remain OFF.)
6. Monitor the low-side pressure at the outdoor unit. The
internal vacuum protection in the compressor and/or
one of the pressure switches prevents full recovery of
the refrigerant into the outdoor unit. When the system
reaches this condition, the suction line service valve
should be shut off and the Pump Down Jumper
moved back to the OFF position.
NOTE - The outdoor control will stay in pump down mode
for five minutes, after which the outdoor control initiates a
compressor shutdown sequence.
7. Use a refrigerant recovery machine to recover the re
maining refrigerant on the indoor side of the system.
Table 4. Field Test, Diagnostic Recall and Program Menu Options
Display Display and action (normal operation)
No Change - idle (*) No Change - idle (*)
Solid . Enter or exit field test and program mode.
Solid Puts unit in diagnostic mode. (Displays ambient, coil, liquid sensor temperatures and any active error codes.)
Solid Clears error history (**)
Solid Enter diagnostic recall mode. Displays up to 10 error codes in memory.
Solid Starts outdoor fan.
String   Enter unit code programming.
*No change indicates the display will continue to show whatever is currently being displayed for normal operations.
**Note once the error history is deleted it cannot be recovered. After the history is deleted, the unit will reset itself.
Table 5. Normal Operation Character Display String
Display Display and action (normal operation) Display and action (configuration and test mode)
.Idle mode — decimal flashes at 1 Hertz > 0.5 second ON, 0.5 second OFF
Cooling operation. Shows and the cooling demand percentage. Example:    pause     pause   
Fan RPM. Shows and the current fan RPM. Example:    pause     pause   
  in the display string represents the active error code(s) in the outdoor unit.
Example:    pause     pause     pause     pause    pause
  in the display string represents the outdoor ambient temperature in F at the outdoor sensor on the outdoor unit.
Example:    pause     pause   
If enabled, in the display string represents the outdoor coil temperature in F at the sensor on the outdoor unit.
Example:    pause     pause    pause    pause. Air conditioning units do not require an outdoor coil sensor. A 10K
resistor, across pins 5 and 6 on the outdoor control sensor harness, prevents false outdoor coil sensor codes. The 10K resistor
causes the 7-segment display to show a constant 77ºF coil (c) temperature value.
If enabled, in the display string represents the outdoor liquid line temperature in F at the sensor on the outdoor unit.
Example:    pause     pause    pause    pause pause     pause
    displays when system is in pump down mode.
TYPICAL 7-SEGMENT ACTIVE COOLING OR HEATING DEMAND DISPLAY STRING
 
COOLING AT
50% DEMAND
OUTDOOR
FAN RPM
OUTDOOR
AMBIENT AIR
TEMP
ACTIVE ERROR
CODE (IF PRESENT)
    
OUTDOOR
COIL TEMP(*)
OUTDOOR LIQUID
LINE TEMP
BY DEFAULT, COOLING OR HEATING, DEMAND, OUTDOOR FAN RPM, ACTIVE ERROR CODES
AND OUTDOOR AMBIENT TEMPERATURE ARE DISPLAYED.
OUTDOOR COIL AND LIQUID LINE TEMPERATURES CAN BE
MANUALLY ENABLED. IF SYSTEM POWER IS RECYCLED, DISPLAY
STRING REVERTS BACK TO DEFAULT (SEE FIGURE 9 TO ENABLE)
* Air conditioning units do not require an outdoor coil sensor. A 10K resistor, across pins 5 and 6 on the outdoor control sensor harness, prevents
false outdoor coil sensor codes. The 10K resistor causes the 7-segment display to show a constant 77ºF coil (c) temperature value.
Figure 8. Typical 7-Segment Demand Display String

18
During thermostat demand of the outdoor control, the 7-segment display shows the cooling or heating (percent demand), fan RPM, error codes if present, and
outdoor ambient, Coil and liquid line temperatures need to be manually enabled to be displayed.
How to enable liquid line temperature information on a 7-segment display
Both coil and liquid line temperatures can be enabled for display
either during normal demand operation or while in idle mode.
PERCENTAGE OF
MAXIMUM CAPACITY
FAN RPM OUTDOOR
AMBIENT
ACTIVE ERRORS
ONLY
OUTDOOR COIL
TEMP (*)
OUTDOOR LIQUID
LINE TEMP
NOTE - If system power is recycled, display string reverts back to
default. Repeat the procedure which enables the outdoor coil and
liquid line temperature information. All temperatures are dis
played in Fahrenheit.
      
Outdoor control is either in IDLE
mode or heating / cooling
demand)
To enable temperature display, push
and hold button next to 7-segment
display until dash symbol appears
and immediately release button.
Once dash starts flashing, proceed
to next step.
Wait until unit returns
to a active demand or
idle mode.
Push and hold the button until the solid
appears on the 7-segment display.
Then, immediately release the button.
Yes
__

Push and hold button until the
flashing stops flashing then
release button. The display shows
the coil and liquid line temperature if
there is an active demand running. 

NOTE - The coil and liquid line temperature readings are temporarily shown on the outdoor 7-segment display when the Comfort Sync™ diagnostic screen is
accessed.
Figure 9. Enabling Liquid Line Temperature Information

19
Configuring Unit
When installing a replacement outdoor control, the unit selection code may have to be manually assigned using the 7-seg
ment display and push button on the control. The unit code sets unit type, capacity and outdoor fan RPM.

Outdoor control is in IDLE mode
(No heating or cooling demand)
To enter unit selection
mode, push and hold the
button next to the 7-segment
display until dash symbol
appears and immediately
release button. Once dash
starts flashing, proceed to
next step.
Turn room thermostat
to OFF
Push and hold button until the solid
 sequence is displayed on the
7-segment display then immediately
release the button. This
configuration sequence allows the
installer to select unit selection code
(number combination) that matches
the outdoor unit type and inverter.
If three horizontal bars display in any
part of the 7-segment display string
during power-up, the outdoor
control did not store the unit
selection code. If this occurs, the
configuration sequence for that
section of the display string must be
repeated.
Yes No
−
−
−
_
_

−
−
−
NOTE - Either the PU sequence
will repeat 5 times and if a
selection is not made the control
will return to idle mode.
NOT
SELECTED
SELECTED
Configuring Unit Selection Code
Power-up - Unit selection code (two-digit number) displayed
represents unit size code (outdoor unit capacity).
During initial power-up, firmware version, unit type, unit capacity
and unit selection code will appear on the 7-segment display.
17
19
21
22
24
26
28
29
2-TON HEAT PUMP
3-TON HEAT PUMP
4-TON HEAT PUMP
5-TON HEAT PUMP
2-TON AIR CONDITIONER
3-TON AIR CONDITIONER
4-TON AIR CONDITIONER
5-TON AIR CONDITIONER
SELECTED
NOT
SELECTED
UNIT SELECTION
CODE
1. When the correct unit section code is displayed, release but
ton immediately. [Display flashes.]
2. Push and hold button until selection stops flashing during
one of the three cycles. [Release push button]
3. If selection is not made during those three cycles the control
returns to idle mode.
The outdoor control stores the unit type, automatically exits the con
figuration mode and resets.
UNIT SELECTION
CODES
Press and hold the button during
the  cycling display.
UNIT
 
EXAMPLE 7-SEGMENT DISPLAY STRING
FIRMWARE
VERSION
UNIT
TYPE
UNIT
CAPACITY
UNIT
CODE
.
IDLE MODE
(NO DEMAND)
.
If three horizontal bars are shown in the 7-segment display
during power-up, the outdoor control did not store the last
configuration setting. If this happens, the configuration se
quence for that setting must be repeated.
Figure 10. Configuring Unit Selection Code

20
Reconfiguring Outdoor Control using
Comfort Sync Wi-Fi®Thermostat
If any component of the HVAC system is changed, e.g. re
placing an outdoor sensor, reconfiguring the system is
required. To begin reconfiguring a system, select the
Setup tab.
System Overview
Refer to the Thermostat Installer Setup Guide for configur
ation procedures.
IMPORTANT
Some scroll compressors have internal vacuum
protector that will unload the scrolls when suction
pressure goes below 20 psig. A hissing sound will be
heard when the compressor is running unloaded.
Protector will reset when low pressure in system is raised
above 40 psig. DO NOT REPLACE COMPRESSOR.
The outdoor control provides the following functions:
DInternal switching of outputs.
DCompressor anti-short-cycle delay (adjustable
through the thermostat interface.
DFive-strike lockout function.
DHigh (S4) and low (S87) pressure switches.
DAmbient (RT13) and liquid line (RT36) temperatures
monitoring and protection.
COMPRESSOR PROTECTION — FIVE-STRIKE
LOCKOUT
The five-strike lockout function is designed to protect the
compressor from damage. The five-strike feature is used
for both high (S4) and low (S87) pressure switches.
Resetting Five-Strike Lockout
Once the condition has been rectified, power to the outdoor
control Rterminal must be cycled OFF.
Diagnostic Information
The following diagnostic information is available through
the thermostat's user interface. Refer to the thermostat In
staller's System Setup Guide.
DCompressor anti-short-cycle delay timer status
DCooling rate
DCompressor shift delay timer status
DHigh pressure switch status
DLow pressure switch status
DCompressor top cap switch status
DLiquid line temperature
DOutdoor ambient temperature
DOutdoor fan RPM
DCompressor active alarm
DCompressor Hz
DInverter compressor short cycle
DHeat sink temperature
Installer Test
Verify the proper operation of the system by running the In
staller Test feature through the thermostat interface. Refer
to the Installer System Setup Guide.
COMPRESSOR SHORT CYCLING DELAY
The outdoor control protects the compressor from:
DShort cycling (five minutes) during initial power-up.
DInterruption in power to the unit.
DPressure or sensor trips.
DDelay after demand is removed.
The delay is set by default for 300 seconds (five minutes)
but can be changed through the thermostat interface.
Available settings are 60, 120, 180, 240 and 300 seconds.
CRANKCASE HEATER (HR1)
Compressors in all units are equipped with a 40-watt belly-
band-type crankcase heater. HR1 prevents liquid from
accumulating in the compressor. HR1 is controlled by the
crankcase heater thermostat.
CRANKCASE HEATER THERMOSTAT (S40)
Thermostat S40 controls the crankcase heater in all units.
S40 is located on the liquid line. When liquid line temperat
ure drops below 50°F, thermostat S40 closes, energizing
HR1. The thermostat opens, de-energizing HR1, once li
quid line temperature reaches 70°F.