TROUBLESHOOTING
38
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.
Symptoms of Abnormal Operation
Associated
LED Code
2
Fault Description(s)
Possible Causes
Corrective Action
Cautions and Notes
• Furnace fails to operate.
• Integrated control module
diagnostic
LED
provides
no
signal
.
OFF
• 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 integrated
control module fuse
with 3A automotive
fuse.
• Read precautions in
“Electrostatic
Discharge" section of
manual.
• LED is Steady On.
CONTINUOUS ON
• Normal Operation
• Normal Operation
• None
• Normal Operation
• Furnace fails to operate.
• Integrated control
module diagnostic
LED
is
flashing
ONE
(1) flash.
1 FLASH
• Furnace lockout due to an
excessive number of
ignition "retries"
(3 total)
1
.
• Failure to establish
flame. Cause may be no
gas to burners, front cover
pressure switch stuck open,
bad igniter or igniter
alignment, improper
orifices, 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,
improper induced draft
blower performance.
• 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. Sand sensor if
coated and/or oxidized.
• Check flue piping for
blockage, proper
length, elbows, and
termination.
• Verify proper induced
draft blower
performance.
• Turn power OFF prior
to repair.
• Igniter is fragile,
handle with care.
• Sand flame sensor with
emery cloth.
• See "Vent/ Flue Pipe"
section for piping
details.
• Furnace fails to operate.
• Integrated control
module diagnostic
LED
is
flashing
TWO
(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 power OFF prior
to repair.
• Replace pressure
switch with proper
replacement part.
ON
1
2
