507607-03
Issue 1827
Page 15 of 23
Seven-Segment Display Alert Codes
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.
E180
Outdoor air temperature sensor failure. Only shown if
shorted or out of range (Communicating systems only)
Compare outdoor sensor resistance to temperature
resistance charts in unit installation instructions. Replace
sensor pack if necessary. At beginning of (any) configuration,
furnace or air handler control will sense outdoor air and
discharge air temperature sensor(s) If detected (reading
in range), appropriate feature will be set as installed and
that could be seen in 'About ' screen. In normal operation
after control recognizes sensors, alarm will be sent if valid
temperature reading is lost. To get rid of setting and alarm,
redo configuration and make sure that temperature sensor is
marked as not installed in indoor Unit ‘About’ screen. When
indoor unit control is replaced thermostat will ‘tell’ new control
if temperature sensor is in system or not. Clears 30 seconds
after fault recovered.
E409
LSOM - Compressor low voltage.
Secondary voltages below 18VAC. After 10 minutes, operation
is discontinued. Clears the code after voltage is higher than
20VAC for 2 seconds or after power reset.
E410
The outdoor unit pressure is below the required limit.
Unit pressure is below the lower limit. The system is shut
down. The low pressure switch for HFC410A will open at
40 PSIG and close at 90 PSIG. 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 closes or after a power rest.
NOTE
:
Additional codes may be found in the Comfort Sync room thermostat manual.
Table 5. 7-Segment Alert and System Status Codes
