Appendix - Goodman *MH8 Installation Instructions Manual

T T T T T
R R R R R OUBLESHOO OUBLESHOO OUBLESHOO OUBLESHOOTING TING TING TING
OUBLESHOO TING
Associated
Symptoms of
LED Code
Abnormal Operation
• Furnace fails to operate.
• Integrated control
LED LED
module diagnostic LED LED LED
provides no signal no signal no signal no signal.
no signal
• Furnace fails to operate.
• Furnace fails to operate.
• Integrated control
module diagnostic LED LED is LED LED
LED
flashing ONE ONE (1) flash. ONE ONE ONE
• Furnace fails to operate.
• Integrated control
LED LED
module diagnostic LED LED LED is
flashing TWO TWO TWO TWO TWO (2) flashes.
• Induced draft blower runs
continuously with no
further furnace operation.
• Integrated control
module diagnostic LED LED is LED LED LED
flashing THREE THREE THREE THREE 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.
C C C C C
H A RT T T T T H A R H A R
H A R H A R
Fault
Description(s)
2
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.
• Furnace lockout due
to an excessive
1
number of ignition
1 1 1 1 1
attempts. (3 total)
1 FLASH
• Auxiliary Limit Open
• Pressure switch
2 circuit is closed.
• Induced draft blower
is not is not is not operating. is not is not
2 FLASHES
• Pressure switch
circuit not closed.
3
• Induced draft blower
is is is is is operating.
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.
• 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.
• Induced draft blower
pressure switch contacts
sticking.
• Shorts in pressure switch
circuit.
• 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.
28
Corrective
Action
• Assure 115 and 24 volt • Turn power OFF
power to furnace
integrated control
module.
• Replace integrated
• Check integrated control
module fuse (3A). Replace
if necessary.
• Check for possible shorts
• Turn power OFF
in 115 and 24 volt circuits.
prior to repair.
Repair as necessary.
• Read precautions in
• Replace bad integrated
"Electrostatic
control module.
Discharge" section
of manual.
• Locate and correct gas
• Turn power OFF
interruption.
• Replace or realign
• Igniter is fragile,
igniter.
• Check flame sense
• Clean flame sensor
signal. Sand sensor if
coated and/or
• See "Combustion
oxidized.
• Check flue piping for
blockage, proper
length, elbows, and
termination.
• Verify proper induced
• See Product Data
draft blower
performance.
• Check circulator
blower speed and
performance. Correct
speed or replace
blower if necessary.
• Turn power OFF
• Replace induced draft
prior to repair.
blower pressure
switch.
• Replace pressure
switch with proper
• Repair short.
replacement part.
• Inspect pressure
• Turn power OFF
switch hose. Repair, if
prior to repair.
necessary,
• See "Combustion
• Inspect flue for
and Ventilation Air
blockage, proper
Requirements"
length, elbows, and
and "Category I
termination.
Venting (Vertical
Venting)" section
• Correct pressure
for details.
switch setpoint or
contact motion.
• Replace pressure
switch with proper
• Tighten or correct
replacement part.
wiring connection.
Cautions
& Notes
prior to repair.
control module fuse
with 3A automotive
fuse.
prior to repair.
handle with care.
with steel wool.
and Ventilation Air
Requirements" and
"Category I Venting
(Vertical Venting)"
section for details.
Bulletin for
allowable rise range
and proper
circulator speed.