Troubleshooting Charts - Goodman GMS8 Installation & Operating Instructions Manual

Associated
Symptoms of Abnormal
Operation
LED Code
• Furnace fails to operate.
• Integrated control
module diagnostic LED
provides no signal.
• Furnace fails to operate.
• Integrated control
module diagnostic LED
is lit continuously.
• Furnace fails to operate.
• Integrated control
module diagnostic LED
is flashing ONE (1)
1 FLASH
flash.
• Furnace fails to operate.
• Integrated control
module diagnostic LED
is flashing TWO (2)
2 FLASHES
flashes.
• Induced draft blower
runs continuously with
no further furnace
operation.
3 FLASHES
• Integrated control
module diagnostic LED
is flashing THREE (3)
flashes.
1 Integrated control module will automatically attempt to reset from lockout after one hour.
IO-242
Troubleshooting Chart
Fault Description(s)
2
• No 115 volt power to
NONE
furnace, or no 24
volt power to
integrated control
module.
• Blown fuse or circuit
breaker.
• Integrated control
module has an
internal fault.
• Furnace lockout due
to an excessive
1
number of ignition
"retries" (3 total) or
"recycles (5 total) .
1
• Auxiliary Limit Open
• Pressure switch
circuit is closed.
2
• Induced draft blower
is not operating.
• Pressure switch
circuit not closed.
3
• Induced draft blower
is operating.
Possible Causes
• 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.
• Failure to establish flame.
Cause may be no gas to
burners, 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 or
improper induced draft
blower performance.
• Insufficient conditioned air
over the heat exchanger.
Blocked filters, restrictive
ductwork, improper
circulator blower speed, or
failed circulator blower.
• Induced draft blower
pressure switch contacts
sticking.
• Shorts in pressure switch
circuit.
• Pressure switch hose
blocked, pinched or
connected improperly.
• Blocked flue or weak
induced draft blower.
• Incorrect pressure switch
setpoint or malfunctioning
switch contacts.
• Loose or improperly
connected wiring.
27
Corrective Action Cautions and Notes
• Assure 115 and 24 volt • Turn power OFF
power to furnace prior to repair.
integrated control
module.
• Check integrated control
module fuse (3A).
• Replace integrated
Replace if necessary.
control module
fuse with 3A
• Check for possible shorts
automotive fuse.
in 115 and 24 volt
circuits. Repair as
necessary.
• Replace bad integrated • Turn power OFF
control module. prior to repair.
• Read precautions
in "Electrostatic
Discharge" section
of manual.
• Turn power OFF
• Locate and correct
prior to repair.
gas interruption.
• Igniter is fragile,
• Replace or realign
handle with care.
igniter.
• Sand flame sensor
• Check flame sense
with emery cloth.
signal. Sand sensor if
coated and/or
• See "Combustion
oxidized.
and Ventilation Air
Requirements" and
• Check flue piping for
"Category I
blockage, proper
Venting (Vertical
length, elbows, and
Venting)" section
termination.
for details.
• Verify proper induced
• See Product Data
draft blower
Bulletin for
performance.
allowable rise
• Check circulator
range and proper
blower speed and
circulator speed.
performance. Correct
speed or replace
blower if necessary.
• Replace induced draft • Turn power OFF
blower pressure prior to repair.
switch.
• Replace pressure
• Repair short. switch with proper
replacement part.
• Turn power OFF
• Inspect pressure
prior to repair.
switch hose. Repair, if
necessary,
• See "Combustion
and Ventilation
• Inspect flue for
Air
blockage, proper
Requirements"
length, elbows, and
and "Category I
termination.
Venting (Vertical
• Correct pressure
Venting)" section
switch setpoint or
for details.
contact motion.
• Replace pressure
• Tighten or correct
switch with proper
wiring connection.
replacement part.
5/04