Goodman GMS8 Installation & Operating Instructions Manual page 30

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.
• Normal furnace
operation.
• Integrated control
module diagnostic LED
is flashing SEVEN (7)
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.
Applies to GMS8/GDS8/GHS8 Models only.
3
TROUBLESHOOTING CHART
Associated
Fault Description(s)
LED Code
2
• Primary limit
circuit is open.
4
4 FLASHES
• Flame sensed
with no call
5
for heat.
5 FLASHES
• Rollout limit open.
6
6 FLASHES
• Flame sense
microamp signal is
7
low.
7 FLASHES
• Polarity of 115
C
volt power is
reversed.
CONTINUOUS
FLASHING
steady on • Normal operation.
Possible Causes
• Insufficient conditioned
air over the heat
exchanger. Blocked
filters, restrictive
ductwork, improper
circulator blower speed,
or failed circulator
blower.
• 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.
• Flame sensor is coated/
oxidized.
• Flame sensor incorrectly
positioned in burner
flame.
• Lazy burner flame due to
improper gas pressure
or combustion air.
• Polarity of 115 volt AC
power to furnace or
integrated control module
is reversed.
• Poor unit ground.
30
Corrective Action Cautions and Notes
• Check filters and
ductwork for blockage.
Clean filters or remove
obstruction.
• See Product Data
• Check circulator blower
speed and performance.
Correct speed or replace
blower if necessary.
• Turn power
• Correct short at flame
sensor or in flame
sensor wiring
• Check burners for
• See "Vent/Flue
proper alignment.
• Check flue and air inlet
piping for blockage,
proper length, elbows,
and termination.
• Replace induced
Correct as necessary.
• Check induced draft
blower for proper
performance.
Replace, if necessary.
• Tighten or correct
wiring connection.
• Sand flame sensor is
• Turn power OFF
coated/oxidized.
• Inspect for proper sensor • Clean 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.
• Review wiring diagram to
correct polarity.
• Verify proper ground.
Correct if necessary.
• Check and correct wiring.
• Turn power OFF
prior to repair.
Bulletin for
allowable rise
range and proper
circulator speed.
OFF prior to
repair.
Pipe" section for
piping details.
draft blower
with proper
replacement part.
prior to repair.
sensor with steel
wool.
Pipe" section for
piping details.
for proper gas
pressure.
• Turn power OFF
prior to repair.