Troubleshooting Chart - Goodman GMS8 Installation & Operating Instructions Manual

Symptoms of Abnormal
Operation
• Circulator blower runs
continuously. No furnace
operation.
• Integrated control module
diagnostic LED is flashing
FOUR (4) flashes.
• Furnace fails to operate.
• Integrated control module
diagnostic LED is flashing
SIX (6) flashes.
• Induced draft blower runs
continuously. No furnace
operation.
• Integrated control module
diagnostic LED is flashing
continuously.
• Induced draft blower
runs continuously. No
furnace operation.
• Integrated control
module diagnostic LED
is flashing SEVEN (7)
flashes.
• LED is steady on
IO-242

Troubleshooting Chart

Associated
Fault Description(s)
LED Code 2
• Primary limit
circuit is open.
4
4 FLASHES
6
6 FLASHES
• Polarity of 115
volt power is
C
reversed.
CONTINUOUS
FLASHING
• Flame sense
microamp signal is
7
low.
7 FLASHES
on steady • Flame sensed with
no call for heat.
• Normal operation.
Possible Causes
• Insufficient conditioned air
over the heat exchanger.
Blocked filters, restrictive
ductwork, improper
circulator blower speed,
or failed circulator blower.
• Flame rollout.
• Misaligned burners,
blocked flue and/or air
inlet pipe, or failed
induced draft blower.
• Loose or improperly
connected wiring.
• Polarity of 115 volt AC
power to furnace or
integrated control module
is reversed.
• Poor unit ground.
• Flame sensor is coated/
oxidized.
• Flame sensor incorrectly
positioned in burner
flame.
• Lazy burner flame due to
improper gas pressure or
combustion air.
• Short to ground in flame
sense circuit.
• Lingering burner flame.
• Slow closing gas valve
28
Corrective Action Cautions and Notes
• Check filters and
ductwork for blockage.
Clean filters or remove
obstruction.
• See Product
• Check circulator blower
speed and performance.
Correct speed or replace
blower if necessary.
• Check burners for proper • See "Vent/Flue
alignment.
• Check flue and air inlet
piping for blockage,
proper length, elbows,
and termination. Correct
• Replace pressure
as necessary.
• Check induced draft
blower for proper
performance. Replace, if
necessary.
• Tighten or correct wiring
connection.
• Review wiring diagram to • Turn power OFF
correct polarity.
• Verify proper ground.
Correct if necessary.
• Check and correct wiring.
• Sand flame sensor is • Turn power OFF
coated/oxidized.
• Inspect for proper sensor
• Sand flame
alignment.
• Check inlet air piping for
blockage, proper length,
• See "Vent/Flue
elbows, and termination.
• Compare current gas
pressure to rating plate
• See rating plate
info. Adjust as needed.
• Correct short at flame
• Turn power OFF
sensor or in flame
sensor wiring.
• Check for lingering
flame
• Verify proper operation
of gas valve
• Turn power OFF
prior to repair.
Data Bulletin for
allowable rise
range and proper
circulator speed.
Pipe" section for
piping details.
switch with
proper
replacement part.
prior to repair.
prior to repair.
sensor with
emery clot.
Pipe" section for
piping details.
for proper gas
pressure.
prior to repair.
5/04