
44
■
Furnace fails to
operate.
■
Integrated
control module
diagnostic LED
is flashing
2 flashes.
2 flashes
■
Pressure switch
circuit is closed.
■
Induced draft
blower is not
operating.
■
Induced draft blower
pressure switch
contacts sticking.
■
Shorts in pressure
switch circuit.
■
Replace induced draft
blower pressure
switch.
■
Repair short.
■
Turn off power
prior to repair.
■
Replace pressure
switch with
correct
replacement part.
■
Induced draft
blower runs
continuously
with no further
furnace
operation.
■
Integrated
control module
diagnostic LED
is flashing
3 flashes.
3 flashes
■
Pressure switch
circuit is not
closed.
■
Induced draft
blower is
operating.
■
Pressure switch hose
blocked, pinched or
connected improperly.
■
Blocked flue and/or inlet
air pipe, blocked drain
system or weak induced
draft blower.
■
Incorrect pressure
switch setpoint or
malfunctioning switch
contacts.
■
Loose or improperly
connected wiring.
■
Inspect pressure
switch hose. Repair/
replace, if necessary.
■
Inspect flue and/or
inlet air piping for
blockage, proper
length, elbows and
termination.
■
Check drain system.
Correct as necessary.
■
Correct pressure
switch setpoint or
contact motion.
■
Tighten or correct
wiring connection.
■
Turn off power
prior to repair.
■
Replace pressure
switch with
correct
replacement part.
■
Replace induced
draft blower with
correct
replacement part.
■
Circulator
blower runs
continuously.
No furnace
operation.
■
Integrated
control module
diagnostic LED
is flashing
4 flashes.
4 flashes
■
Primary limit or
auxiliary limit
circuit is open.
■
Insufficient conditioned
air over the heat
exchanger. Blocked
filters, restrictive
ductwork, improper
circulator blower speed,
or failed circulator
blower.
■
Faulty primary limit
switch.
■
Loose or improperly
connected wiring.
■
Check primary limit
switch. Replace if
necessary.
■
Check filters and
ductwork for blockage.
Clean filters or remove
obstruction.
■
Check circulator
blower speed and
performance. Correct
speed or replace
blower if necessary.
■
Tighten or correct
wiring connection.
■
Turn off power
prior to repair.
■
Replace primary
switch with
correct
replacement part.
■
Replace
circulator blower
with correct
replacement part.
■
Induced draft
blower and
circulator
blower runs
continuously.
No furnace
operation.
■
Integrated
control module
diagnostic LED
is flashing
5 flashes.
5 flashes
■
Flame sensed
with no call for
heat.
■
Short to ground in flame
sense circuit.
■
Correct short at flame
sensor or in flame
sensor wiring.
■
Turn off power
prior to repair.
Symptoms of
Abnormal
Operation
Associated
LED Code
Fault Description Possible Causes
Corrective Actions
Notes and
Cautions