Troubleshooting Chart - Goodman GMSS96 Installation Instructions Manual

T C
ROUBLESHOOTING HART
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.
LED Flash code will cease if power to the control module is interrupted through the disconnect or door switch.
2
Associated
Fault
Description(s)
LED Code
2
•No 115 volt power
NONE
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 excessive
1
number of ignition
"retries" (3 total)
1 FLASH
• Pressure switch
circuit is closed.
2
• Induced draft
blower is not
2 FLASHES
operating.
• Pressure switch
circuit not closed.
3
• Induced draft
blower is operat-
ing.
3 FLASHES
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.
• Normal Operation
•Failure to establish flame.
Cause may be no gas to
burners, front cover
pressure switch stuck
.
1
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),
front cover pressure
switch opening, or
improper induced draft
blower performance.
•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.
42
Corrective Action
•Assure 115 and 24 volt •Turn power OFF
power to furnace prior to repair.
integrated control
•Replace inte-
module.
grated control
•Check integrated module fuse with
control module fuse 3A automotive
(3A). Replace if fuse.
necessary.
•Read precautions
•Check for possible in "Electrostatic
shorts in 115 and 24 Discharge"
volt circuits. Repair section of manual.
as necessary.
•Replace bad inte-
grated control module.
• Normal Operation
•None
•Locate and correct •Turn power
gas interruption. OFF prior to
repair.
•Check front cover
pressure switch
operation (hose,
wiring, contact
operation). Correct if
necessary.
•Igniter is
•Replace or realign
fragile, handle
igniter.
with care.
•Check flame sense
•Sand flame
signal. Sand sensor if
sensor with
coated and/or
emery cloth.
oxidized.
•See "Vent/
•Check flue piping for
Flue Pipe"
blockage, proper
section for
length, elbows, and
piping details.
termination.
•Verify proper induced
draft blower perfor-
mance.
•Turn power OFF
•Replace induced draft
prior to repair.
blower pressure
switch.
•Replace pressure
switch with
•Repair short.
proper replace-
ment part.
•Inspect pressure
•Turn power
switch hose. Repair,
OFF prior to
if necessary,
repair.
•Inspect flue and/or
•Replace
inlet air piping for
pressure
blockage, proper
switch with
length, elbows, and
proper
termination. Check
replacement
drain system.
part.
Correct as
necessary.
•Correct pressure
switch setpoint or
contact motion.
•Tighten or correct
wiring connection.
Cautions &
Notes