41
■
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.
■
No furnace
operation.
■
Integrated
control module
diagnostic LED
is flashing
6 flashes.
6 flashes
■
Rollout limit
switch open.
■
Integrated
control module
fuse is blown.
■
Flame rollout.
■
Misaligned burners,
blocked flue and/or air
inlet pipe or failed
induced draft blower.
■
Loose or improperly
connected wiring.
■
Short in 24-volt AC
control circuits or safety
circuits.
■
Faulty rollout limit
switch.
■
Check burners for
proper alignment.
■
Check flue and air inlet
piping for blockage,
proper length, elbows
and termination.
Correct as necessary.
■
Check rollout limit
switch. Replace if
necessary.
■
Check induced draft
blower for proper
performance. Replace
if necessary.
■
Tighten or correct
wiring connection.
■
Repair short in 24-volt
AC control/safety
circuit(s).
■
Replace integrated
control module fuse
(3A).
■
Turn off power
prior to repair.
■
Replace induced
draft blower with
correct
replacement part.
■
Replace
integrated control
module fuse with
3A automotive
fuse.
■
Read precautions
in “Electrostatic
Discharge”
section of
manual.
■
Replace rollout
limit switch with
correct
replacement part.
■
See “Vent/Fluie
Pipe” section for
piping details.
Symptoms of
Abnormal
Operation
Associated
LED Code
Fault Description Possible Causes
Corrective Actions
Notes and
Cautions