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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
271
Critical
(Furnace) The furnace is in Watchguard
mode. The furnace low pressure switch is
open.
This is a five strike condition during a single demand. Check pressure (inches w.c.) of low
pressure switch closing during a heat call. Measure operating pressure (inches w.c.).
Inspect vent and combustion air inducer for correct operation and restriction. The alarm/
fault will clear on successful ignition.
272
Critical
(Furnace) The furnace is in Watchguard
mode. The furnace low pressure switch is
open during run mode.
Check operation of low pressure switch to see if it is stuck open during a heat call. Meas
ure operating pressure (inches w.c.). Inspect vent and combustion air inducer for correct
operation and restriction. The alarm/fault will clear when a heat call ends successfully.
273
Critical
(Furnace) The furnace is in Watchguard
mode. The furnace flame is going off during
a heating cycle.
Check microamperes of flame sensor using thermostat diagnostics. Clean or replace
sensor. Measure voltage of neutral to ground to ensure good unit ground. The alarm/fault
will clear when a heat call ends successfully.
274
Critical
(Furnace) The furnace limit switch has been
open for more than 3 minutes.
The system will go into Watchguard mode. Check firing rate and air flow. Check for block
age. The alarm/fault will clear when a heat call ends successfully.
275
Critical
(Furnace) The furnace flame is out of se
quence.
The system will go into Watchguard mode. Shut off gas. Check for gas valve leak. The
alarm/fault will clear on next successful ignition.
276
Critical
(Furnace) The furnace is not able to calib
rate or the high pressure switch opened or
failed to close in run mode.
The system will go into Watchguard mode. Check vent system and pressure
switch wiring connections. The fault/alarm will clear when the furnace calibrates itself
successfully.
290
Critical
(Furnace) There is a problem with the fur
nace ignition circuit.
The system will go into Watchguard mode. Measure resistance of hot surface igniter.
Replace the hot surface ignitor it is not within specifications. The alarm/fault will clear on
next successful ignition.
291
Critical
(Furnace) The heating airflow is below the
minimum required level.
The system will go into Watchguard mode. Check for dirty filters and other air flow restric
tions. Check blower performance. The alarm/fault will clear when a heat call ends suc
cessfully.
292
Critical
(Furnace / Air Handler) The
(furnace or
airhandler)
indoor blower motor will not
start.
The system will go into Watchguard mode. Indoor blower motor unable to start. This could
be due to seized bearing, stuck wheel, obstruction etc. Replace motor or wheel if as
sembly does not operate or meet performance standards. The alarm/fault clears after the
indoor blower motor starts successfully.
294
Critical
(Furnace) There is over current in the fur
nace inducer motor.
The system will go into Watchguard mode. Check combustion blower bearings, wiring and
amps. Replace if does not operate or does not meet performance standards. The alarm/
fault clears after inducer current is sensed to be inrange after the ignition following the
Watchguard mode or reset.
295
Minor
(Furnace) The indoor blower motor is over
heating.
Indoor blower motor over temperature (motor tripped on internal protector). Check motor
bearings and amps. Replace if necessary. The alarm/fault clears after blower demand is
satisfied.
