Instruction manual

32
Diagnostic Chart
The dual 7-segment LED display will display an error code that may contain a letter and number. The error code may be used to assist
in troubleshooting the unit.
Symptoms of
Abnormal
Operation
Diagnostic/
Status 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.
Goodman 118 Long
HIGH VOLTAGE!
WARNING
To avoid personal injury or death due to electrical shock, disconnect electrical power
before performing any service or maintenance.