40
TROUBLESHOOTING CHART
•Circulator blower runs
continuously. No furnace
operation.
•Integrated control module
diagnostic
LED
is flashing
FOUR
(4) flashes.
•Check primary/auxiliary
limit. 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 power OFF prior
to repair.
•Replace primary/
auxiliary limit with
proper replacement
part.
•Replace blower with
correct replacement
part.
4
4 FLASHES
•Faulty pirmary or
auxiliary limit switch.
•Insufficient condi-
tioned air over the
heat exchanger.
Blocked filters,
restrictive ductwork,
improper circulator
blower speed, or failed
circulator blower.
•Loose or improperly
connected wiring.
Fault
Description(s)
Possible Causes
Corrective Action
Cautions and Notes
Symptoms of Abnormal
Operation
Associated
LED Code
2
•Normal furnace opera-
tion.
•Integrated control module
diagnostic
LED
is flashing
SEVEN
(7) flashes.
•Flame sense
microamp
signal is low.
•Sand flame sensor.
•Inspect for proper
sensor alignment.
•Compare current gas
pressure to rating plate
info. Adjust as
needed.
•Turn power OFF prior to
repair.
•Clean flame sensor with
steel wool.
•See “Vent/Flue Pipe”
section for piping details.
•See rating plate for
proper gas pressure.
7
7 FLASHES
•Flame sensor is coated/
oxidized.
•Flame sensor incorrectly
positioned in burner
flame.
•Lazy burner flame due to
improper gas pressure
or combustion air.
•Induced draft blower
and circulation blower
runs continuously. No
furnace operation.
•Integrated control
module diagnostic
LED
is flashing
FIVE
(5)
flashes
.
•Flame sensed
with no call for
heat.
•Correct short at flame
sensor or in flame
sensor wiring.
•Turn power OFF
prior to repair.
5
5 FLASHES
•Short to ground in flame
sense circuit.
•Furnace fails to
operate.
•Integrated control
module diagnostic
LED
is flashing
SIX
(6)
flashes.
•No furnace operation.
•Rollout limit
open.
•Integrated
control module
fuse is blown.
•Check burners for proper
alignment.
•Check flue and air inlet
piping for blockage,
proper length, elbows,
and termination. Correct
as necessary.
•Check rollout limit.
Replace if necessary.
•Check induced draft
blower for proper
performance. Replace, if
necessary.
•Tighten or correct wiring
connection.
•Turn power OFF prior to
repair.
•See “Vent/Flue Pipe”
section for piping details.
•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 with
correct replacement part.
6
6 FLASHES
•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.
•Furnace fails to operate.
•Integrated control module
diagnostic
LED
is flashing
continuously
.
•Polarity of 115
or 24 volt
power is
reversed.
•Review wiring diagram to
correct polarity.
•Reverse orange and gray
wires going to trans-
former.
•Verify proper ground.
Correct if necessary.
•Turn power OFF
prior to repair.
C
•Polarity of 115 volt AC
power to furnace or
integrated control module
is reversed.
•Orange and gray wires to
transformer are reversed.
•Poor unit ground.
CONTINUOUS/
7
8 FLASHES
8
•Furnace not operating.
•Integrated control module
diagnostic
LED
is flashing
EIGHT
(8) flashes.
•Problem with
igniter
circuit.
•Improperly connected
igniter.
•Bad igniter.
•Poor unit ground.
•Poor burner ground.
•Faulty integrated control
module.
•Check and correct
wiring from integrated
control module to
igniter.
•Replace bad igniter.
•Check & correct unit
ground wire.
•Replace bad integrated
control module.
• Turn power OFF prior to
repair.
• Replace igniter w/proper
replacment part.
• Read precautions in
“Electrostatic Discharge”
section of manual.
RAPID FLASH
•LED is steady on.
STEADY ON
2
LED Flash code will cease if power to the control module is interrupted through the disconnect or door switch.
•Normal operation.
•Primary or
auxiliary limit
circuit is open.
