Lennox A98USMV Installation Instructions Manual page 62

Code Diagnostic Codes / Status of Equipment
E271 Soft lockout - Exceeded maximum number of
retries. Last retry failed due to the pressure switch
opening.
E272 Soft lockout - Exceeded maximum number of
recycles. Last recycle due to the pressure switch
opening
E273 Soft lockout - Exceeded maximum number of
recycles. Last recycle due to flame failure
E274 Soft lockout - Exceeded maximum number of
recycles. Last recycle failed due to the limit circuit
opening or limit remained open longer than 3
minutes.
E275 Soft lockout - Flame sensed out of sequence.
Flame signal is gone.
E276 Soft lockout calibration failure.
E290 Ignitor circuit fault - Failed ignitor or triggering
circuitry.
E291 Heat airflow restricted below the minimum.
E292 Indoor blower motor unable to start due to
obstructed wheel seized bearings.
E294 Combustion air inducer over current.
E295 Indoor blower motor temperature is too high.
E310 Discharge error temperature sensor failure. Only
shown if shorted or out of range.
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Action Required to Clear and Recover
Check pressure (inches w.c.) of low pressure switch
closing on heat call. Measure operating pressure
(inches w.c.). Inspect vent and combustion air inducer
for correct operation and restriction. Clears when heat
call finishes successfully.
Check operation of low pressure to see if it is stuck
closed on heat call. Check pressure (inches w.c.) of
high pressure switch closing on heat call. Measure
operating pressure. Inspect vent and combustion air
inducer for correct operation and restriction. Clears
when heat call finishes successfully.
Check micro-amperes of flame sensor using control
diagnostics or field installed mode. Clean or replace
sensor. Measure voltage of neutral to ground to ensure
good unit ground. Alert clears after current heat call has
been completed.
Shut down system 1-hour soft lockout. Check firing rate
and air flow. Check for blockage. Clears when heat call
finishes successfully.
Shut off gas. Check for gas valve leak. 1-hour soft
lockout. Clears when flame has been proven stable.
Unable to perform pressure switch calibration. Check
vent system and pressure switch wiring connections.
1-hour soft lockout. Clears when calibration has finished
successfully.
Measure resistance of hot surface igniter. Replace if
open or not within specifications. 1-hour soft lockout.
Clears when flame has been proven stable.
Check for dirty filter and airflow restriction. Check
blower performance. 1-hour soft lockout. Cleared when
heat call finishes successfully.
Indoor blower motor unable to start (seized bearing,
stuck wheel, etc.) Replace motor or wheel if assembly
does not operate or meet performance standards.
1-hour soft lockout. Clears after circulator successfully
starts.
Check combustion blower bearings wiring and
amps. Replace if does not operate or does not meet
performance standards. Clears after inducer current is
sensed to be in-range after the ignition following the soft
lockout or reset.
Indoor blower motor over temperature (motor tripped
on internal protector). Check motor bearings and amps.
Replace if necessary. Cleared after blower demand is
satisfied.
Compare discharge sensor resistance to temperature
resistance charts in installation instructions.. Replace
sensor if necessary. Cleared in Communicating
mode 30 seconds after fault recovered. In Non-
Communicating mode cleared after the current heat call
is completed.
Issue 2346 508364-01