506860-03
Issue 1946
Page 17 of 27
Code
Diagnostic Codes / Status of Equipment
Action Required to Clear and Recover
E105
Device communication problem - No other devices on RS
BUS (Communication system).
Equipment is unable to communicate. Indicates numerous
message errors. In most cases, errors are related to electrical
noise. Make sure high voltage power is separated from
RSBus. Check for mis-wired and/or loose connections
between the stat, indoor unit, and outdoor unit. Check for a
high voltage source of noise close to the system. Fault clears
after communication is restored.
E120
Unresponsive device (Communicating systems only).
Usually caused by delay in outdoor unit responding to indoor
unit poling. Recycle power. Check all wiring connections.
Cleared after unresponsive device responds to any inquiry.
E124
Active communicating thermostat signal missing for more
than 3 minutes (Communicating systems only).
Equipment lost communication with the thermostat. Check
four wiring connections, ohm wires, and cycle power at the
thermostat. Alert stops all services and waits for heartbeat
message from thermostat (subnet controller). Cleared after
valid thermostat (subnet) message is received.
E125
Control failed self-check, internal error, failed hardware.
Will restart if error recovers, Integrated control not
communicating Covers hardware errors (flame sense
circuit faults, pin shorts, etc).
Hardware problem on the control. Cycle power on control.
Replace if problem prevents service and is persistent. Cleared
300 seconds after fault recovered.
E126
Control internal communication problem.
Hardware problem on the control. Cycle power on control.
Replace if problem prevents service and is persistent. Cleared
300 seconds after fault recovered.
E131
Corrupted control parameters (Verify configuration of
system) (Communicating systems only).
Reconfigure the system. Replace control if heating or cooling
is not available. Only applicable in the communicating mode
not in startup. Exit from Commissioning and Execute Se+
factory Default mode. Control will still operate on default
parameter settings.
NOTE
:
Additional codes may be found in the Comfort Sync room thermostat manual.
Table 5. 7-Segment Alert and System Status Codes
7-Segment Alert and System Status Codes
Alert codes are displayed using the 7-segment display
located on the outdoor control.
NOTE:
System fault and lockout 7-segment display
alarm codes take precedence over system status codes
(cooling, heating stages or defrost/dehumidification). Only
the latest active fault or lockout alarm code, if present, will
be displayed. If no fault or lockout codes are active, then
system status codes are routinely displayed.
The 7-segment will display an abnormal condition (error
code) when detected in the system. A list of the codes are
shown in Table 5.
Resetting Alert Codes
Alert codes can be reset manually or automatically:
Manual Reset
Manual reset can be achieved by one of the following
methods:
• Disconnecting R wire from the main control’s R
terminal.
•
Turning the indoor unit off and back ON again. After
power up, all existing codes will display for 60 seconds
and then clear.
Automatic Reset
After an alert is detected, the main control continues to
monitor the unit’s system and compressor operations.
When/if conditions return to normal, the alert code is turned
off automatically.
