• Furnace fails to operate.
• Integrated control module LED
display provides
error code.
• Problem w ith igniter
circuit.
• Improperly connected
igniter.
• Shorted igniter.
• Poor unit ground.
• Igniter relay fault on
integrated control module.
• Furnace fails to operate on
high stage; furnace operates
normally on low stage.
• Integrated control module LED
display provides
error code.
• High stage pressure
sw itch circuit is
closed at start of
heating cycle.
• Induced draft
blow er is operating.
• Furnace is
operating on low
stage only
• High stage pressure
sw itch contacts sticking.
• Shorts in pressure sw itch
circuit w iring.
• Furnace fails to operate on
high stage; furnace operates
normally on low stage.
• Integrated control module LED
display provides
error
code.
• High stage pressure
sw itch circuit is not
closed.
• Induced draft
blow er is operating.
• Furnace is
operating on low
stage only
• Pressure sw itch hose
blocked pinched, or
connected improperly.
• Blocked fue and/or inlet air
pipe, blocked drain system
or w eak induced draft
blow er.
• Incorrect pressure sw itch
set point or malfunctioning
sw itch contacts.
• Loose or improperly
connected w iring.
• Furnace fails to operate.
• Integrated control module LED
display provides
error code.
• Polarity of 115 volt
AC is reversed
• Polarity of 115 volt AC
pow er to furnace or
integrated module is
revered.
• Poor unit ground
• Furnace fails to operate.
• Integrated control module LED
display provides
error code.
• Gas valve is not
energized w hen it
should be.
• External Gas Valve
Error
• Misw ired gas valve circuit
• Open gas valve circuit
• Gas valve relay on
integrated control board
stuck open
• Check w iring in gas valve circuit
• Replace integrated control board
• Turn pow er OFF prior to
repair.
• Review w iring diagram to correct
polarity.
• Verify proper ground. Correct if
necessary.
• Check and correct w iring.
• Turn pow er OFF prior to
repair.
• Check and correct w iring from
integrated control module to igniter.
• Replace shorted igniter.
• Check and correct unit ground
w iring.
• Check igniter output from control.
Replace if necessary.
• Turn pow er OFF prior to
repair.
• Replace igniter w ith correct
replacement part.
• Replace control w ith
correct replacement part.
• Replace high stage pressure
sw itch.
• Repair short in w iring
• Turn pow er OFF prior to
repair.
• Replace pressure sw itch
w ith proper replacement part.
• Inspect pressure sw itch hose.
Repair/replace if necessary.
• Inspect fue and/or inlet air piping
for blockage, proper length,
elbow s, and termination. Check
drain system. Correct as
necessary.
• Check induced draft blow er
performance. Correct as
necessary.
• Correct pressure sw itch set
point or contact motion.
• Tighten or correct w iring
connection.
• Turn pow er OFF prior to
repair.
• Replace pressure sw itch
w ith proper replacement part.
• Replace induced draft
blow er w ith proper
replacement part.
Symptoms of Abnormal
Operation
Diagnostic /
Status LED
Codes
Possible Causes
Corrective Actions
Notes & Cautions
Fault Description
• Induced draft blow er and
circulator blow er runs
continuously. No furnace
operation.
• Integrated control module LED
display provides
error code.
• Flame sensed w ith
no call for heat.
• Short to ground in fame
sense circuit.
• Lingering burner fame.
• Slow closing gas valve.
• No furnace operation.
• Integrated control module LED
display provides
error code.
• Open Fuse
• Short in low voltage
w iring
• Normal furnace operation.
• Integrated control module LED
display provides
error code.
• Flame sense micro
amp signal is low
• Flame sensor is
coated/oxidized.
• Flame sensor incorrectly
positioned in burner fame.
• Lazy burner fame due to
improper gas
pressure or combustion air.
• Locate and correct short in low
voltage w iring
• Turn pow er OFF prior to
repair.
• Replace fuse w ith 3-amp
automotive type
• Clean flame sensor if
coated/oxidized.
• Inspect for proper sensor
alignment.
• Check inlet air piping for
blockage, proper length, elbow s,
and termination.
• Compare current gas pressure to
rating plate. Adjust as needed.
• Turn pow er OFF prior to
repair.
• Clean flame sensor w ith
steel w ool.
• See "Vent/Flue Pipe"
section for piping details.
• See rating plate for proper
gas pressure.
• Correct short at fame sensor or
in fame sensor w iring.
• Check for lingering fame.
• Verify proper operation of gas
valve.
• Turn pow er OFF prior to
repair.
TROUBLESHOOTING
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