TROUBLESHOOTING
45
PCBBF134 CONTROL BOARDS
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.
• 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
replacement part.
• Replace masonry
vent kit limit switch
with correct
replacement part.
•
Furnace lockout due
to an excessive
number of ignition
attempts. (3 total)
1
• Locate and correct
gas interruption.
• Replace or realign
igniter.
• Check flame sense
signal. Clean sensor
if coated and/or
oxidized.
• Check flue piping for
blockage, proper
length, elbows, and
termination.
• Verify proper
induced draft blower
performance.
• 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.
• Clean flame
sensor with steel
wool.
• See “Combustion
and Ventilation Air
Requirements” and
“Category I
Venting (Vertical
Venting)” section
for details.
• 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.
• Main power interruption
during heat cycle causing
auxiliary limit to open.
• "auxillary limit switch
open" - wired in series
with the gas valve.
• 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 replace-
ment 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.
• Inspect masonry
chimney and flue;
remove blockage.
• 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.
• Blockage in the flue
• Pressure switch
circuit not closed.
• Induced draft
blower
is
operating.
• If installed, manual
reset limit switch is
open on Masonry
Vent Kit (MVK).
• Induced draft blower
runs continuously with
no further furnace
operation.
• Integrated control
module diagnostic
LED
is flashing
THREE
(3)
flashes.
3
3 FLASHES
• Integrated control
module has an
internal fault.
• Integrated control module
has an internal fault.
• Turn power OFF
prior to repair.
• Read precautions
in “Electrostatic
Discharge” section
of manual.
• Furnace fails to
operate.
• No 115 volt power
to furnace, or no 24
volt power to
integrated control
module.
• Blown fuse or
circuit breaker.
• Manual disconnect switch
OFF, door switch open, or
24 volt wires improperly
connected or loose.
• Blown fuse or circuit
breaker.
• Assure 115 and 24 volt
power to furnace
integrated control
module.
• Check for possible
shorts in 115 and 24 volt
circuits. Repair as
necessary.
• Replace bad integrated
control module.
• Furnace fails to
operate.
• Integrated control
module diagnostic
LED
provides
no signal
.
NONE
Cautions
& Notes
Corrective
Action
Possible
Causes
Fault
Description(s)
Symptoms of
Abnormal Operation
Associated
LED Code
2