Goodman Mfg MH95/ACSH96/AMEH96/ GCH95/GME95/GCH9 Troubleshooting Chart, Symptoms of Abnormal

Models: GAS-FIRED WARM AIR FURNACE MH95/ACSH96/AMEH96/ GCH95/GME95/GCH9

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TROUBLESHOOTING CHART

TROUBLESHOOTING CHART

Symptoms of Abnormal

Associated

 

Fault Description(s)

Possible Causes

Corrective Action

Cautions and Notes

Operation

LED Code2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

• Furnace fails to operate.

 

NONE

• No 115 volt power to

• Manual disconnect switch

• Assure 115 and 24 volt

• Turn power OFF

• Integrated control module

 

 

 

 

furnace, or no 24 volt

OFF, door switch open, or

power to furnace

prior to repair.

diagnostic LED provides

 

 

 

 

power to integrated

24 volt wires improperly

integrated control module.

• Replace integrated

no signal.

 

 

 

 

control module.

connected or loose.

• Check integrated control

control module

 

 

 

 

• Blown fuse or circuit

• Blown fuse or circuit

module fuse (3A).

fuse with 3A

 

 

 

 

 

breaker.

breaker.

Replace if necessary.

automotive fuse.

 

 

 

 

 

 

 

• Check for possible shorts

• Read precautions

 

 

 

 

• Integrated control

• Integrated control module

in 115 and 24 volt circuits.

in “Electrostatic

 

 

 

 

 

module has an

Repair as necessary.

Discharge” section

 

 

 

 

 

internal fault.

has an internal fault.

• Replace bad integrated

of manual.

 

 

 

 

 

 

 

control module.

 

• LED is Steady On.

 

ON

 

 

• Normal Operation

•Normal Operation

• None

•Normal Operation

 

 

 

 

 

 

 

 

 

CONTINUOUS

 

 

 

 

 

 

 

ON

 

 

 

 

 

 

 

 

 

 

 

 

 

• Furnace fails to operate.

 

 

 

• Furnace lockout due

• Failure to establish flame.

• Locate and correct gas

• Turn power

• Integrated control module

1

 

 

to an excessive

Cause may be no gas to

interruption.

OFF prior to

diagnostic LED is

 

 

 

 

number of ignition

burners, front cover

• Check front cover

repair.

flashing ONE (1) flash.

 

1 FLASH

 

“retries” (3 total)1.

pressure switch stuck open,

pressure switch

 

 

 

 

 

 

 

bad igniter or igniter

operation (hose, wiring,

 

 

 

 

 

 

 

alignment, improper orifices,

contact operation).

 

 

 

 

 

 

 

or coated/oxidized or

Correct if necessary.

 

 

 

 

 

 

 

improperly connected flame

• Replace or realign

• Igniter is

 

 

 

 

 

 

sensor.

 

 

 

 

 

 

igniter.

 

 

 

 

 

 

 

fragile, handle

 

 

 

 

 

 

 

• Check flame sense

 

 

 

 

 

 

• Loss of flame after establish-

with care.

 

 

 

 

 

 

signal. Sand sensor if

• Sand flame

 

 

 

 

 

 

ment. Cause may be

 

 

 

 

 

 

coated and/or oxidized.

 

 

 

 

 

 

interrupted gas supply, lazy

sensor with

 

 

 

 

 

 

• Check flue piping for

 

 

 

 

 

 

burner flames (improper gas

emery cloth.

 

 

 

 

 

 

pressure or restriction in flue

blockage, proper

• See “Vent/Flue

 

 

 

 

 

 

length, elbows, and

 

 

 

 

 

 

and/or combustion air

Pipe” section

 

 

 

 

 

 

termination.

 

 

 

 

 

 

piping), front cover pressure

for piping

 

 

 

 

 

 

• Verify proper induced

 

 

 

 

 

 

switch opening, or improper

details.

 

 

 

 

 

 

induced draft blower

draft blower perfor-

 

 

 

 

 

 

 

performance.

mance.

 

 

 

 

 

 

 

 

 

 

• Furnace fails to operate.

 

 

 

Pressure switch

• Induced draft blower

• Replace induced draft

• Turn power OFF

• Integrated control module

2

 

 

circuit is closed.

pressure switch contacts

blower pressure switch.

prior to repair.

diagnostic LED is

 

 

 

Induced draft

sticking.

 

• Replace pressure

flashing TWO (2) flashes.

2 FLASHES

 

blower is not

• Shorts in pressure switch

• Repair short.

switch with proper

 

 

 

 

 

operating.

circuit.

 

replacement part.

 

 

 

 

 

 

 

 

 

• Induced draft blower runs

 

 

 

Pressure switch

• Pressure switch hose

• Inspect pressure

• Turn power

continuously with no

3

 

circuit not closed.

blocked, pinched or

switch hose. Repair, if

OFF prior to

further furnace operation.

 

 

 

Induced draft blower

connected improperly.

necessary,

repair.

• Integrated control module

3 FLASHES

 

is operating.

• Blocked flue and/or inlet air

• Inspect flue and/or inlet

• Replace

diagnostic LED is

 

 

 

 

 

pipe, blocked drain system,

air piping for blockage,

pressure

flashing THREE (3)

 

 

 

 

 

or weak induced draft

proper length, elbows,

switch with

flashes.

 

 

 

 

 

blower.

and termination. Check

proper

 

 

 

 

 

 

• Incorrect pressure switch

drain system. Correct

replacement

 

 

 

 

 

 

setpoint or malfunctioning

as necessary.

part.

 

 

 

 

 

 

switch contacts.

• Correct pressure switch

 

 

 

 

 

 

 

• Loose or improperly

setpoint or contact

 

 

 

 

 

 

 

connected wiring.

motion.

 

 

 

 

 

 

 

 

• Tighten or correct

 

 

 

 

 

 

 

 

wiring connection.

 

 

 

 

 

 

 

 

 

 

1Integrated control module will automatically attempt to reset from lockout after one hour.

2LED Flash code will cease if power to the control module is interrupted through the disconnect or door switch.

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Goodman Mfg MH95/ACSH96/AMEH96/ GCH95/GME95/GCH9 Troubleshooting Chart, Symptoms of Abnormal, Fault Descriptions