32
Symptoms of
Abnormal
Operation
Diagnostic/
Staus LED
Code
Fault Description Possible Causes
Corrective Actions
Notes and Cautions
■
Furnace fails to
operate.
■
Integrated
control module
diagnostic LED
display
provides no
signal.
None
■
No 115-volt
power to
furnace, or no
24-volt power to
integrated
control module.
■
Blown fuse or
circuit breaker.
■
Internal fault in
Integrated
control module.
■
Manual disconnect
switch Off, door
switch open or
24-volt wire
improperly
connected or
loose.
■
Blown fuse or
circuit breaker
■
Integrated control
module has an
internal fault.
■
Assure 115-volt power
to the furnace, and
24-volt power to
integrated control
module
■
Check integrated
control module fuse.
Replace with 3A
automotive fuse, if
necessary.
■
Check for possible
shorts in 115-volt and
24-volt circuits. Repair
as necessary.
■
Replace bad
integrated control
module.
■
Turn off power prior to
repair.
■
Replace integrated
control module fuse
with 3A automotive
fuse.
■
Read precautions in
“Electrostatic
Discharge” section of
manual.
■
Replace integrated
control module with
current replacement
parts.
■
LED display
indicates “OP.”
OP
■
Normal
operation
■
Normal operation
■
None
■
Normal operation
■
Furnace fails to
operate.
■
Integrated
control module
LED display
provides “E0”
error code.
E0
■
Furnace lockout
due to an
excessive
number of
ignition “retries”
(3 total).
■
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.
■
Locate and correct gas
interruption.
■
Check front cover
pressure switch
operation (hose,
wiring, contact
operation). Correct if
necessary.
■
Replace or realign
igniter. Igniter is fragile,
handle gently.
■
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 off power 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
LED display
provides “E1”
error code.
E1
■
Low-stage
pressure switch
circuit is closed
at start of
heating cycle.
■
Low-stage
pressure switch
contacts sticking.
■
Shorts in pressure
switch circuit
wiring.
■
Replace low-stage
pressure switch.
■
Repair short in wiring.
■
Turn off power prior to
repair.
■
Replace pressure
switch with correct
replacement part.
