Goodman Furnace Troubleshooting

If you are thinking of getting a furnace for commercial purposes, don’t hesitate and get one made by Goodman. However, the repair can become something real for you. It occasionally happens despite the quality and Goodman brand isn’t an exception. In this case the best thing you can do is to look into the troubleshooting guide given here.

Goodman ACS Series Furnace Troubleshooting

Symptoms of Abnormal OperationFault Description(s)Possible Causes
- Motor rocks slightly when starting.- This is normal start-up for variable speed motor.
- Motor won't start.- No movement.- Manual disconnect switch off or door switch open.
- Blown fuse or circuit breaker.
- 24 Vac wires miswired.
- Unseated pins in wiring harness connectors.
- Bad motor/control module.
- Moisture present in motor or control module.
- Motor rocks, but won't start.- Loose motor mount.
- Blower wheel not tight on motor shaft.
- Bad motor/control module.
- Motor oscillates up & down while being tested off of blower.- It is normal for motor to oscillate with no load on shaft.
- Motor starts, but runs erratically.- Varies up and down or intermittent.- Variation in 115 Vac to motor.
- Unseated pins in wiring harness connectors.
- Erratic CFM command from "BK" terminal.
- Improper thermostat connection or setting.
- Moisture present in motor/control module.
- "Hunts" or "puffs" at high CFM (speed).- Incorrect or dirty filter(s).
- Incorrect supply or return ductwork.
- Incorrect blower speed setting.
- Motor starts, but runs erratically.- Stays at low CFM despite system call for cool or heat CFM.- 24 Vac wires miswired or loose.
- "R" missing/not connected at motor.
- Fan is delay mode.
- Stays at high CFM.- "R" missing/not connected at motor.
- Fan is delay mode.
- Blower won’t shut off.- Current leakage from controls into G, V, or W.
- Air noise.- High static creating high blower speed.
- Incorrect supply or return ductwork.
- Incorrect or dirty filter(s).
- Incorrect blower speed setting.
- Excessive noise.- Noisy blower or cabinet.- Loose blower housing, panels, etc.
- High static creating high blower speed.
- Air leaks in ductwork, cabinets, or panels.
- "Hunts" or "puffs' at high CFM (speed).- High static creating high blower speed.
- Incorrect or dirty filter(s).
- Incorrect supply or return ductwork.
- Incorrect blower speed setting.
- Evidence of Moisture.- Motor failure or malfunction has occurred and moisture is present.- Moisture in motor/control module.

Goodman CVC9 95 Furnace Troubleshooting

LED StatusPossible CausesCorrective Action(s)
Red Communications LED: Off 1 Flash• None• None
• Communications Failure• Depress Learn Button
• Verify that bus BIAS and TERM dipswitches are in the ON position.
2 Flashes• Control power up• None
• Learn button depressed
Off• No power to furnace• Check fuses and circuit breakers; replace/reset
• Open fuse• Replace blown fuse
• Communications error• Check for shorts in low voltage wiring in fu mace/system
• Reset network by depressing learn button
• Check data 1/ data 2 voltaqes
Green Receive LED: 1 Steady Flash• Broken/ disconnected data wire(s)• Check communications wiring (data 1/ data 2 wires)
• Furnace is installed as a non communicating / traditional system• Check wire connections at terminal block
• Verify furnace installation type (non communicating / traditional or communicating)
• Check data 1/ data 2 voltages
Rapid Flashing• Control is “talking“ on network as expected• None
On Solid• Data 1 and data 2 wires reversed at furnace, thermostat, or ComfortNet compatible outdoor AC/HP• Check communications wiring (data 1/data 2 wires)
• Short between data 1 and data 2 wires• Check wire connections at terminal block
• Short between data 1 or data 2 wires and R (24VAC) or C (24VAC common)• Check data 1/ data 2 voltages

Goodman CVC96 Furnace Troubleshooting

LEDDescriptionCorrective Action
Red Communications LED: 1 FlashCommunications Failure•Depress Leam Button that bus BIAS and TERM dipswitches are in the ON position.
2 FlashesOut-of-box resetNone
Off•Nopower •Communications error•Check fuses and circuit breakers; replace/reset
•Replace blown fuse
•Check for shorts in low voltage wiring in furnace/ system
•Reset network by depressing leam button
•Check data 1/ data 2 voltages
Green Receive LED: 1 Steady FlashNo network found•Check communications wiring (data 1/data 2 wires)
•Check wire connections at terminal block furnace installation type (legacy/ traditional or communicating) Check data 1/ data 2 voltages
Rapid FlashingNormal network traffcNone
On SolidData 1/ Data 2 miss-wire•Check communications wiring (data 1/data 2 wires)
•Check wire connections at terminal block •Check data 1/ data 2 voltages

Goodman GMSS96 Furnace Troubleshooting

Symptoms of Abnormal OperationFault Description(s)Possible Causes
• Furnace falls to operate.• No 115 volt power to furnace, or no 24 volt power to integrated control module.•Manual disconnect switch OFF, door switch open, or 24 volt wires Improperly connected or loose.
•Integrated control module diagnostic LED provides no signal.• Blown fuse or circuit breaker.• Blown fuse or circuit breaker.
• Integrated control module has an internal fault.•Integrated control module has an Internal fault.
• LED Is Steady On.• Normal Operation• Normal Operation
• Furnace fails to operate.• Furnace lockout due to an excessive number of ignition "retries" (3 total)'.• Failure to establish flame. Cause may be no gas to burners, front cover pressure switch stuck open, bad Igniter or Igniter alignment, Improper orifices, or coated/oxidized or Improperly connected flame sensor.
• Integrated control module diagnostic LED is flashing ONE (1) flash.• Loss of flame after establishment. Cause may be interrupted gas supply, lazy burner flames (Improper gas pressure or restriction in flue and/or combustion air piping), front cover pressure switch opening, or Improper Induced draft blower performance.
• Furnace falls to operate.• Pressure switch circuit Is closed.• Induced draft blower pressure switch contacts sticking.
•Integrated control module diagnostic LED is flashing TWO (2) flashes.• Induced draft blower is not operating.•Shorts in pressure switch circuit.
• Induced draft blower runs continuously with no further furnace operation.• Pressure switch circuit not closed.• Pressure switch hose blocked, pinched or connected improperly.
•Integrated control module diagnostic LED Is flashing THREE (3) flashes.• Induced draft blower Is operating.• Blocked flue and/or inlet air pipe, blocked drain system, or weak induced draft blower.
•Incorrect pressure switch setpolnt or malfunctioning switch contacts.
• Loose or Improperly connected wiring.
• Circulator blower runs continuously. No furnace operation.• Primary or auxiliary limit circuit Is open.• Faulty pirmary or auxiliary limit switch.
• Integrated control module diagnostic LED Is flashing FOUR (4) flashes.• Insufficient conditioned air over the heat exchanger. Blocked filters, restrictive ductwork, Improper circulator blower speed, or failed circulator blower.
• Loose or Improperly connected wiring.
• Induced draft blower and circulation blower runs continuously. No furnace operation.• Rame sensed with no call for heat.• Short to ground In flame sense circuit.
•Integrated control module diagnostic LED Is flashing FIVE (5) flashes.
• Furnace falls to operate.• Rollout limit open.• Flame rollout.
• Integrated control module diagnostic LED Is flashing SIX (6) flashes.•Integrated control module fuse is blown.•Misaligned burners, blocked flue and/or air inlet pipe, or failed induced draft blower.
• No furnace operation.• Loose or improperly connected wiring.
• Short in 24 volt AC control circuits or safety circuits.
• Faulty rollout limit.
• Normal furnace operation.• Flame sense signal Is low.• Flame sensor Is coated/oxidized.
•Integrated control module diagnostic LED Is flashing SEVEN (7) flashes.• Flame sensor incorrectly positioned In burner flame.
• Lazy burner flame due to Improper gas pressure or combustion air.
• Furnace not operating.• Problem with Igniter circuit.• Improperly connected Igniter.
• Integrated control module diagnostic LED Is flashing EIGHT <8) flashes.• Bad Igniter.
• Poor unit ground.
• Poor burner ground.
• Faulty Integrated control module.
• Furnace falls to operate.• Polarity of 115 or 24 volt power is reversed.• Polarity of 115 volt AC power to furnace or integrated control module is reversed.
• Integrated control module diagnostic LED is flashing continuously.•Orange and gray wires to transformer are reversed.
• Poor unit ground.
• LED is steady on.• Normal operation.

Goodman MEC961205DN Furnace Troubleshooting

SymptomsFault DescriptionCautions
•Furnace fails to operate •Control board LED is off•Defective disconnect switch •defective door switch • No 115 volt power »No 24 volt power•Confirm electrically safe condition before proceeding with repairs
•Furnace is waiting for a call•Furnace is not receiving a call•Confirm electrically safe condition before proceeding with work
•Furnace fan only is running•Furnace is receiving a call for fan (24 volts on G terminal•Confirm electrically safe condition before proceeding with work
•Normal operation with low stage call for cooling (Ylo&G)•Normal operation with low stage call for cooling (Ylo & G)•Confirm electrically safe condition before proceeding with work
•Normal operation with high or single stage call for cooling (Y&G)•Normal operation with high or single stage call for cooling (Y&G)•Confirm electrically safe condition before proceeding with work
•Normal operation with low stage call for heat (Wl)•Normal operation with low stage call for heat (Wl)•Confirm electrically safe condition before proceeding with work
•Normal operation with high or single stage call for heat•Normal operation with high or single stage call for heat•Confirm electrically safe condition before proceeding with work
•Furnace does not operate, three Amber flashes on control board•W2 call present without Wl•Confirm electrically safe condition before proceeding with repairs
•Furnace does not operate, four Amber flashes on control board•Ylo or Y call present without G•Confirm electrically safe condition before proceeding with repairs
•Furnace does not operate, rapid Amber flashes on control board•Low flame sense current•Clean flame rod with steel wool. Confirm electrically safe condition before proceeding with repairs
•Furnace does not operate, one Red flash on control board•Flame sensed when no flame should be present•Confirm electrical and gas safe conditions before proceeding with repairs
•Furnace does not operate, two Red flashes on control board, possible inducer operation•Pressure switch stuck closed•Confirm electrically safe condition before proceeding with repairs
•Furnace does not operate, three Red flashes on control board•Low fire pressure switch stuck open•Confirm electrically safe condition before proceeding with repairs

Goodman XMVM97 Series Furnace Troubleshooting

Symptoms of Abnormal OperationPossible CausesCorrective Actions
• Furnace fails to operate • Integrated control module LED display provides IF error code.• Improper wiring to the furnace a integrated control module.• Assure proper wiring to furnace and integrated control module.
• Verify power to the furnace and integrated control module is stable and within specifications.
• Replace bad integrated control module.
• LED display indicates On• Normal operation• None
• Furnace fails to operate • Integrated control module LED display provides EO erra code.• Failure to establish flame. Cause may be no gas to burners, front cover pressure switch stuck open, bad igniter a igniter alignment improper aifices, a coatedfoxidized a improperly connected flame sensa.• Locate and correct gas interruption.
• Loss of flame after establishment. Cause may be interrupted gas supply, lazy burner flames (improper gas pressure a restriction in flue and/a combustion air piping), front cover pressure switch opening, a improper induced draft blower performance.• Check front cover pressure switch operation (hose, wiring, contact operation). Correct if necessary. Make sure furnace is draining properly.
• Replace a realign ignite.
• Check flame sense signal. Sand sense if coated and for oxidized.
• Check flue piping fan blockage, proper length, elbows, and termination.
• Verify proper induced draft blower performance.
• Furnace fails to operate. • Integrated control module LED display provides E1 error code. • ComfortNet thermostat scrolls “Check Furnace' message.• Low stage pressure switch contacts sticking.• Replace low stage pressure switch.
• Shorts in pressure switch circuit wiring.• Repair short in wiring.
• Induced draft blower runs continuously with no further furnace operation. • Integrated control module LED display provides E2 erra code. • ComfortNet th ermostat “ Cal I f a Service" icon illuminated. • ComfortNet thermostat scrolls “Check Furnace' message.• Pressure switch hose blocked pinched, a connected improperly.• Inspect pressure switch hose. Repamt-eplace if necessary.
• Blocked flue and/br inlet air pipe, blocked drain system a weak induced draft blower.• Inspect flue and/a inlet air piping fa blockage, proper length, elbows, and termination.
• Incorrect pressure switch set point a malfunctioning switch contacts.• Check drain system. Correct as necessary.
• Loose a improperly connected wiring.• Check induced draft blower performance. Correct as necessary.
• Inducer not running.• Correct pressure switch set point a contact motion.
• H fitting atmospheric port blocked.• Tighten a correct wiring connection.
• Clean H fitting.
• Circulator blower runs continuously. No furnace operation. • Integrated control module LED display provides E3 erra code.• Insufficient conditioned air over the heat exchanger. Blocked filters, restrictive ductwork, improper circulator blower speed, a failed circulator blower motor.• Check filters and ductwork fa blockage. Clean filters a remove obstruction.
• Loose a improperly connected wiring.• Check circulator blower speed and performance. Carect speed a replace blower motor if necessary.
• Tighten a correct wiring connection.