TROUBLESHOOTING
43
1
Integrated control module will automatically attempt to reset from lockout after one hour.
2
LED Flash code will cease if power to the control module is interrupted through the disconnect or door switch.
• Furnace lockout
due to an exces-
sive number of
ignition “retries” (3
total)
1
.
• Locate and correct gas
interruption.
• Check front cover
pressure switch
operation (hose, wiring,
contact operation).
Correct if necessary.
• Replace or realign
igniter.
• Check flame sense
signal. Clean sensor if
coated and/or oxidized.
• Check flue piping for
blockage, proper length,
elbows, and termination.
• Verify proper induced
draft blower perfor-
mance.
• Turn power
OFF prior to
repair.
• Igniter is
fragile, handle
with care.
• Clean flame
sensor.
• See “Vent/
Flue Pipe”
section for
piping details.
• Furnace fails to
operate.
• Integrated control
module diagnostic LED
is flashing ONE (1)
flash.
1
1 FLASH
• Failure to establish flame.
Cause may be no gas to
burners, front cover
pressure switch stuck
open, bad igniter or igniter
alignment, improper
orifices, or coated/
oxidized or improperly
connected flame sensor.
• Loss of flame after
establishment. Cause may
be interrupted gas supply,
lazy burner flames
(improper gas pressure or
restriction in flue and/or
combustion air piping),
front cover pressure
switch opening, or
improper induced draft
blower performance.
• Pressure switch
circuit is closed.
• Induced draft
blower is not
operating.
• Replace induced
draft blower
pressure switch.
• Repair short.
• Turn power OFF
prior to repair.
• Replace pressure
switch with
proper replace-
ment part.
• Furnace fails to operate.
• Integrated control module
diagnostic LED is flashing
TWO (2) flashes.
2
2 FLASHES
• Induced draft blower
pressure switch contacts
sticking.
• Shorts in pressure switch
circuit.
• Inspect pressure
switch hose. Repair,
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.
• 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.
• Pressure switch
circuit not closed.
• Induced draft
blower is
operating.
• Induced draft blower
runs continuously with
no further furnace
operation.
• Integrated control
module diagnostic LED
is flashing THREE (3)
flashes.
3
3 FLASHES
• Turn power
OFF prior to
repair.
• Replace
pressure
switch with
proper
replacement
part.
Fault
Description(s)
Possible Causes
Associated
• Normal Operation • Normal Operation • None
• Normal Operation
ON
CONTINUOUS
ON
• No 115 volt power
to furnace, or no
24 volt power to
integrated control
module.
• Blown fuse or
circuit breaker.
• Integrated control
module has an
internal fault.
• Manual disconnect
switch OFF, door
switch open, or 24 volt
wires improperly
connected or loose.
• Blown fuse or circuit
breaker.
• Integrated control
module has an internal
fault.
• Assure 115 and 24 volt
power to furnace integrated
control module.
• Check integrated control
module fuse (3A). Replace
if necessary.
• Check for possible shorts
in 115 and 24 volt circuits.
Repair as necessary.
• Replace bad integrated
control module.
• Turn power OFF
prior to repair.
• Replace
inte-
grated
control
module fuse with
3A automotive
fuse.
• Read precautions
in “Electrostatic
Discharge”
section of manual.
• Furnace fails to
operate.
• Integrated control
module diagnostic LED
provides no signal.
NONE
Fault
Description(s)
Possible Causes Corrective Action
Cautions and
Notes
Symptoms of Abnormal
Operation
Associated
LED Code
2
• LED is Steady On.
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