iComfort
Wi‐Fi
®
7-Day Programmable Communicating Thermostat
29
Table 1. Alert Codes and Troubleshooting
Critical alerts are displayed on Home (user) screen, in the Homeowner alert button, and in
the Installer alert button. Minor and Moderate alerts are found only in the Installer alert
button.
Alert
Code
Steps to clear
Alert Text
Priority
370
Critical
(Furnace) The furnace control board has not
received 24VAC power for 2 minutes or
more.
Control sees the loss of 24VAC for 2 minutes .Terminate all services and wait for
interlock switch to close. The alarm will clear when 24VAC is continuously sensed on DS
terminal for a minimum of 10 seconds or on a power reset. If 2 stage with float switch, the
IFC control RDS is open.
380
Moderate /
Critical
(Equipment Interface Module) Interlock relay
failure (IFC or AHC mode only)
Interlock relay is energized, but input is not sensed after 3 seconds. There will be no heat
ing or cooling due to this error. Deenergize interlock relay and energize after 5 minutes if
demand is still present.
381
Moderate /
Critical
(Equipment Interface Module) Interlock relay
stuck (IFC or AHC modes only)
Interlock relay continuously sensed (with relay off). No heating and cooling operations.
Alarm clears 30 seconds after fault clears.
382
Moderate
(Equipment Interface Module) Relay W1 fail
ure (IFC and AHC modes only)
W1 relay energized, but input is not sensed after three seconds.
400
Critical
(Outdoor Unit) The compressor internal
overload has tripped.
Thermostat demand Y1 is present; but, compressor is not running. Check power to unit.
Clears the error after current is sensed in both RUN and START sensors for at least 2
seconds, or after service is removed, or after power reset.
401
Moderate
(Outdoor Unit) Either the compressor ran for
more than 18 hours continuously trying to
cool the home or the refrigerant pressure in
the system is low.
Compressor ran more than 18 hours to satisfy a single thermostat demand. Will not lock
out system. If 2 stage, units with blinking LED light controls, unit will run in low speed; units
with 7segment display will display code, but continue to run in high speed. If a Heat
Pump, and if outdoor temp is less than 65 degrees, code is ignored. Clears the error after
30 consecutive normal run cycles or power reset. Also monitors low pressure switch trips.
402
Critical
(Outdoor Unit) Either the discharge or suc
tion pressure level is outoflimits, or the is
compressor overloaded.
Discharge or suction pressure outoflimits, or compressor overloaded. Clears the error
after 4 consecutive normal compressor run cycles.
403
Moderate
(Outdoor Unit) The compressor ran for less
than 3 minutes to satisfy a thermostat de
mand.
Compressor runs less than 3 minutes to satisfy a thermostat demand. Clears the error
after 4 consecutive normal run cycles or power reset.
404
Critical
(Outdoor Unit) The compressor rotor is
locked up. This could be due to a short cir
cuiting of the run capacitor, seizing of the
bearings or excessive liquid refrigerant etc.
Compressor rotor locked up due to run capacitor short, bearings are seized, excessive
liquid refrigerant, etc. (NOTE: May need to install hard start kit). Clears the error after 4
consecutive normal run cycles or after power reset.
405
Critical
(Outdoor Unit) The compressor circuit is
open. This could be due to a power discon
nection, open fuse etc.
Compressor circuit open (due to power disconnection, open fuse, etc.) Clears the error
after 1 normal compressor run cycle.
