Goodman GMH95 Installation Instructions Manual page 43

Symptoms of
Abnormal Operation
• Circulator blower runs
continuously. No furnace
operation.
• Integrated control module
diagnostic LED is flashing
FOUR (4) flashes.
• Induced draft blower and
circulator blower runs
continuously. No furnace
operation.
• Integrated control module
diagnostic LED is flashing
FIVE (5) flashes.
• Furnace fails to operate.
• Integrated control module
diagnostic LED is flashing
SIX (6) flashes.
• No furnace operation.
• Normal furnace
operation.
• Integrated control module
diagnostic LED is
flashing SEVEN (7)
flashes.
• Furnace not operating.
• Integrated control module
diagnostic LED is
flashing EIGHT (8)
flashes.
• Induced draft blower runs
continuously. No furnace
operation.
• Integrated control module
diagnostic LED is flashing
continuously.
• LED is steady on
2 LED Flash code will cease if power to the control module is interrupted through the disconnect or door switch.
TROUBLESHOOTING CHART
Fault
Associated
Description(s)
LED Code 2
• Primary limit
4 circuit is open.
4 FLASHES
• Flame sensed
5
with no call for
heat.
5 FLASHES
• Rollout limit open.
6
• Integrated control
module fuse is
blown.
6 FLASHES
• Flame sense
microamp signal is
7
low.
7 FLASHES
• Problem with
igniter circuit.
8 FLASHES
• Polarity of 115
C
or 24 volt
power is
reversed.
CONTINUOUS
FLASHING
STEADY
• Normal operation.
ON
Possible Causes
• Insufficient conditioned air
over the heat exchanger.
Blocked filters, restrictive
ductwork, improper
circulator blower speed, or
failed circulator blower.
• Faulty primary limit switch.
• Loose or improperly
connected wiring.
• Short to ground in flame
sense circuit.
• Flame rollout.
• Misaligned burners,
blocked flue and/or air
inlet pipe, or failed
induced draft blower.
• Loose or improperly
connected wiring.
• Short in 24 volt AC
control circuits or safety
circuits.
•Faulty rollout limit.
• Flame sensor is coated/
oxidized.
• Flame sensor incorrectly
positioned in burner
flame.
• Lazy burner flame due to
improper gas pressure or
combustion air.
• Improperly connected
igniter.
• Bad igniter.
• Poor unit ground.
• Poor burner ground.
• Faulty integrated control
module.
• Polarity of 115 volt AC
power to furnace or
integrated control module
is reversed.
• Red and blue wires to
transformer are reversed.
• Poor unit ground.
43
Corrective Action
• Check primary limit.
• Turn power OFF
Replace if necessary.
• Check filters and
• Replace primary
ductwork for blockage.
Clean filters or remove
obstruction.
• Replace blower
• Check circulator blower
speed and performance.
Correct speed or replace
blower if necessary.
• Tighten or correct wiring
connection.
• Correct short at flame
sensor or in flame
sensor wiring.
• Check burners for proper
• See "Vent/Flue
alignment.
• Check flue and air inlet
piping for blockage,
• Replace induced
proper length, elbows,
and termination. Correct
as necessary.
• Check rollout limit. Replace
• Replace inte-
if necessary.
• Check induced draft
blower for proper
performance. Replace, if
necessary.
• Tighten or correct wiring
• Read precautions
connection.
• Repair short in 24 volt AC
control/safety circuit(s).
• Replace integrated control
• Replace rollout
module fuse (3A).
• Turn power OFF
• Sand flame sensor.
• Inspect for proper sensor
• Clean flame sensor
alignment.
• Compare current gas
• See "Vent/Flue
pressure to rating plate
info. Adjust as needed.
• See rating plate for
• Check and correct wiring • Turn power OFF
from integrated control
module to igniter.
• Replace igniter
•Replace bad igniter.
•Check and correct unit
• Read precautions
ground wiring.
• Replace bad integrated
control module.
• Review wiring diagram to
correct polarity.
• Verify proper ground.
Correct if necessary.
• Reverse red and blue
wires connected to
transformer.
Cautions
& Notes
prior to repair.
switch with proper
replacement part.
with correct
replacement part.
• Turn power OFF
prior to repair.
Pipe" section for
piping details.
draft blower with
proper replace-
ment part.
grated control
module fuse with
3A automotive
fuse.
in "Electrostatic
Discharge"
section of manual.
limit with correct
replacement part.
prior to repair.
with steel wool.
Pipe" section for
piping details.
proper gas
pressure.
prior to repair.
with proper
replacement part.
in "Electrostatic
Discharge"
section of manual.
• Turn power OFF
prior to repair.