35
T
ROUBLESHOOTING
C
HART
Associated
LED Code
2
2
LED Flash code will cease if power to the control module is interrupted through the disconnect or door switch.
Associated
LED Code
2
4
4 FLASHES
• Circulator blower runs
continuously. No furnace
operation.
• Integrated control module
diagnostic
LED
is flashing
FOUR
(4) flashes.
6
6 FLASHES
7
7 FLASHES
•Furnace fails to operate.
•Integrated control module
diagnostic
LED
is flashing
SIX
(6) flashes.
•No furnace operation.
•Normal furnace opera-
tion.
•Integrated control
module diagnostic
LED
is
flashing
SEVEN
(7) flashes.
•Rollout limit
open.
•Integrated control
module fuse is
blown.
•Flame sense
microamp signal is
low.
•Flame sensor is coated/
oxidized.
•Flame sensor incorrectly
positioned in burner
flame.
•Lazy burner flame due to
improper gas pressure or
combustion air.
•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 rating plate for
proper gas
pressure.
•See “Vent/Flue
Pipe” section for
piping details.
•Replace induced
draft blower with
proper replace-
ment 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.
• Primary limit
circuit is open.
•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 heat exchanger.
•Check induced draft blower
for proper performance.
Replace, if necessary.
•Check position of orifice
plate/heat exchanger
shield.
•Tighten or correct wiring
connection.
•Repair short in 24 volt AC
control/safety circuit(s).
•Replace integrated control
module fuse (3A).
•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.
•Induced draft blower and
circulator blower runs
continuously. No furnace
operation.
•Integrated control
module diagnostic
LED
is
flashing
FIVE
(5) flashes.
5
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 power OFF
prior to repair.
•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.
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
switch with proper
replacement part.
•Replace blower
with correct
replacement part.
Cautions
& Notes
Corrective Action
Possible Causes
Fault
Description(s)
Symptoms of
Abnormal Operation
PCBBF134 & PCBBF132 CONTROL BOARDS
