
SYSTEM OPERATION
90
T
ROUBLESHOOTING
C
HART
ADV8, AMV8, ACV9, AMV9, GMV8, GCV9, GMV9
• Furnace lockout
due to an
excessive
number of
ignition “retries”
(3 total)
1
.
• Auxiliary limit
open
• Locate and correct gas
interruption.
• Replace or realign
igniter.
• Check flame sense
signal. Sand sensor if
coated and/or oxidized.
• Check flue piping for
blockage, proper length,
elbows, and termination.
• Verify proper induced
draft blower perfor-
mance.
• Check circulator blower
speed and performance.
Correct speed or
replace blower if
necessary.
• Turn power OFF
prior to repair.
• Igniter is fragile,
handle with care.
• Sand flame sensor
with emery cloth.
• See “Combustion
and Ventilation Air
Requirements” and
“Category I
Venting (Vertical
Venting)” section
for details.
• See Product Data
Bulletin for
allowable rise
range and proper
circulator speed.
• Furnace fails to operate.
• Integrated control
module diagnostic
LED
is flashing
ONE
(1)
flash.
1
1 FLASH
• Failure to establish flame.
Cause may be no gas to
burners, 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 or
improper induced draft
blower performance.
• Insufficient conditioned air
over the heat exchanger.
Blocked filters, restrictive
ductwork, improper
circulator blower speed, or
failed circulator blower.
• Low stage
pressure switch
circuit is closed.
• Induced draft
blower
is not
operating.
• Replace induced draft
blower pressure
switch.
• Repair short.
• Turn power OFF
prior to repair.
• Replace pressure
switch with proper
replacement part.
• Furnace fails to operate.
• Integrated control
module diagnostic
LED
is flashing
TWO
(2)
flashes.
2
2 FLASHES
• Induced draft blower
pressure switch contacts
sticking.
• Shorts in pressure switch
circuit.
• Inspect pressure
switch hose. Repair, if
necessary,
• Inspect flue for
blockage, proper
length, elbows, and
termination.
• Correct pressure
switch setpoint or
contact motion.
• Tighten or correct
wiring connection.
• Pressure switch hose
blocked, pinched or
connected improperly.
• Blocked flue or weak
induced draft blower.
• Incorrect pressure switch
setpoint or malfunctioning
switch contacts.
• Loose or improperly
connected wiring.
• Pressure
switch circuit
not closed.
• Induced draft
blower
is
operating.
• Induced draft blower
runs continuously with
no further furnace
operation.
• Integrated control
module diagnostic
LED
is flashing
THREE
(3)
flashes.
3
3 FLASHES
• Turn power OFF
prior to repair.
• See “Combustion
and Ventilation Air
Requirements”
and “Category I
Venting (Vertical
Venting)” section
for details.
• Replace pressure
switch with
proper replace-
ment part.
• No 115 volt power
to furnace, or no 24
volt power to
integrated control
module.
• Blown fuse or
circuit breaker.
• Intergrated contol
module has an
internal fault
• Manual disconnect switch
OFF, door switch open, or
24 volt wires improperly
connected or loose.
• Blown fuse or circuit
breaker.
• Intergrated contol module
has an internal fault
• Assure 115 and 24 volt
power to furnace
integrated control
module.
• Check integrated control
module fuse (3A).
Replace if necessary.
• Check for possible
shorts in 115 and 24
volt circuits. Repair as
necessary.
• Replace bad intergrated
control module.
• Turn power OFF
prior to repair.
• Replace integrated
control module
fuse with 3A
automotive fuse.
• Read precautions
in “Electrostatic
Discharge” section
of manual.
• Furnace fails to operate.
• Integrated control
module diagnostic
LED
provides
no signal
.
NONE
Fault
Description(s)
Possible Causes
Corrective Action
Cautions and Notes
Symptoms of Abnormal
Operation
Associated
LED Code
2
•
LED
is steady
ON
.
ON
CONTINUOUS
ON
• Normal operation.
• Normal operation.
• None.
• Normal operation.
1
Integrated control module will automatically attempt to reset from lockout after one hour.
2
LED flash code will cease if power to control module is interrupted throught the disconnect or door switch.
4
Applies to ADV8, AMV8, GMV8 only.