Troubleshooting - Amana GMS8 Service Instructions Manual

TROUBLESHOOTING

Symptoms of Abnormal
Operation
• Furnace fails to
operate.
• Integrated control
module diagnostic LED
provides no signal.
• LED is Steady On.
• Furnace fails to
operate.
• Integrated control
module diagnostic LED
is flashing ONE (1)
flash.
• Furnace fails to operate.
• Integrated control module
diagnostic LED is flashing
TWO (2) flashes.
• Induced draft blower
runs continuously with
no further furnace
operation.
• Integrated control
module diagnostic LED
is flashing THREE (3)
flashes.
1
Integrated control module will automatically attempt to reset from lockout after one hour.
2
LED Flash code will cease if power to the control module is interrupted through the disconnect or door switch.
Associated
Associated Fault
Fault
Description(s)
LED Code
2
Description(s)
NONE • No 115 volt power
to furnace, or no
24 volt power to
integrated control
module.
• Blown fuse or
circuit breaker.
• Integrated control
module has an
internal fault.
• Normal Operation
ON
CONTINUOUS
ON
• Furnace lockout
due to an exces-
1
sive number of
ignition "retries" (3
total) .
1
• Pressure switch
circuit is closed.
2
• Induced draft
blower is not
2 FLASHES
operating.
• Pressure switch
circuit not closed.
3
• Induced draft
blower is
3 FLASHES
operating.
PCBBF123(S) CONTROL BOARD
Possible Causes
Possible Causes
• Manual disconnect
• Assure 115 and 24 volt
switch OFF, door
switch open, or 24 volt
wires improperly
• Check integrated control
connected or loose.
• Blown fuse or circuit
breaker.
• Check for possible shorts
• Integrated control
module has an internal
fault.
• Replace bad integrated
• Normal Operation • None
• Failure to establish flame.
Cause may be no gas to
burners, 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), or
improper induced draft
blower performance.
• "auxillary limit switch
open"- wired in series
with the gas valve.
• Induced draft blower
pressure switch contacts
sticking.
• Shorts in pressure switch
circuit.
• Pressure switch hose
blocked, pinched or
connected improperly.
• Blocked flue and/or inlet
air pipe, blocked drain
system, or weak induced
draft blower.
• Incorrect pressure switch
setpoint or malfunctioning
switch contacts.
• Loose or improperly
connected wiring.
Corrective Action Cautions and
• Turn power OFF
prior to repair.
power to furnace integrated
control module.
• Replace inte-
grated control
module fuse with
module fuse (3A). Replace
3A automotive
if necessary.
fuse.
• Read precautions
in 115 and 24 volt circuits.
in "Electrostatic
Repair as necessary.
Discharge"
section of manual.
control module.
• Normal Operation
• Locate and correct gas • Turn power
interruption. OFF prior to
repair.
• Replace or realign
igniter.
• Igniter is
fragile, handle
• Check flame sense
with care.
signal. Clean sensor if
coated and/or oxidized.
• Clean flame
sensor.
• Check flue piping for
blockage, proper length, • See "Vent/
elbows, and termination. Flue Pipe"
section for
• Verify proper induced
piping details.
draft blower perfor-
mance.
• Turn power OFF
• Replace induced
prior to repair.
draft blower
• Replace pressure
pressure switch.
switch with
• Repair short.
proper replace-
ment part.
• Inspect pressure
• Turn power
switch hose. Repair,
OFF prior to
if necessary,
repair.
• Inspect flue for
• Replace
blockage, proper
pressure
length, elbows, and
switch with
termination. Correct
proper
as necessary.
replacement
part.
• Correct pressure
switch setpoint or
contact motion.
• Tighten or correct
wiring connection.
Notes
43