Installation Guide
28
I&O manual
Table 14 - Troubleshooting Chart
TROUBLE SHOOTING CHART
Symptoms of
Abnormal Operation
Associated
LED
Fault Description(s)
Possible reason
Corrective Action
Cautions and Notes
•Furnace fails to
operate.
•Integrated control
module diagnosic
LED provides
NO SIGNAL
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
•Door switch open,
or 24 volt wires
improperly connected
or loose.
•Blown fuse or circuit
breaker
•Integrated control
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 integrated
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 is flashing
ONE (1) flash.
1 FLASH
2
FLASHES
3
FLASHES
4
FLASHES
•Furnace lockout due
to an excessive
number of ignition
attempts.
• 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.
• 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 performance.
• Turn power OFF
prior to repair.
• Igniter is fragile,
handle with care.
• Clean flame
sensor with steel wool.
• Furnace fails to
operate.
•Integrated control
module diagnostic
LED is flashing
TWO (2) flashes
• Pressure switch
circuit is closed.
• Induced draft
blower is not
operating.
• Induced draft blower
pressure switch contacts
sticking.
• Shorts in pressure
switch circuit.
• Replace induced draft
blower pressure switch.
• Repair short.
• Turn power OFF
prior to repair.
• Replace pressure
switch with proper
replacement part.
• Induced draft blower
runs continuously
with no further
furnace operation.
Integrated control
module diagnostic
LED is flashing
THREE (3) flashes.
• Pressure switch
circuit not closed.
Induced draft blower
is operating
• Pressure switch hose
blocked, pinched or
connected improperly
Blocked flue or weak
induced draft blower.
• Incorrect pressure switch
setpoint or malfun,
ctioning switch contacts.
• loose or improperly
connected wiring.
• 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.
• Turn power OFF prior to
repair.
• See •Combustion and
Ventilation Air Requirements"
and •Category I Venting"
section for details.
• Replace pressure switch
with proper replacement part.
• Circulator blower
runs continuously.
No furnace operation.
• Integrated control
module diagnostic
LED is flashing
FOUR (4) flashes.
• Primary limit circuit
is open.
•Reverse flow switch
is open
• Faulty primary or
reverse flow limit switch.
• Insufficient conditioned
air over the heat
exchanger. Blocked
filters, restrictive
ductwork,improper
circulator blower speed,
or failed circulator blower.
• Loose or improperly
connected wiring.
• Check primary or reverse
flow limit switch. Replace
if necessary.
• Check filters and ductwork
for blockage. Clean filters
or remove obstruction.
• Check circulator blower
speed and performance.
Correct speed or replace
blower if necessary.
• Tighten or correct wiring
connection.
• Turn power OFF prior to
repair.
• Replace primary limit with
proper replacement part.
• Replace blower with
correct replacement part.
• Replace reverse flow
switch with proper
replacement part.
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.