39
TROUBLESHOOTING CHART
•Furnace lockout
due to an excessive
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. Sand 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.
•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
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.
•Turn power OFF
prior to repair.
•Replace pressure
switch with proper
replacement 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.
•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
LED Code
2
• Normal Operation
• Normal Operation
•None
• Normal
Operation
•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.
•Furnace fails to
operate.
•Integrated control
module diagnostic
LED
provides
no signal
.
NONE
Corrective Action
Cautions &
Notes
Symptoms of Abnormal
Operation
•LED is Steady On.
•Replace induced draft
blower pressure switch.
•Repair short.
•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.
ON
CONTINUOUS
ON
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.
