Gibson
Gibson Furnaces Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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1 FLASH
Status LED flashes once repeatedly, furnace will not start heating cycle
Ignition Failure / No Flame Detected
2 FLASHES
Status LED flashes twice repeatedly, furnace starts but shuts down shortly after ignition
Pressure Switch Stuck Closed
3 FLASHES
Status LED flashes three times, inducer runs but burners do not light
Pressure Switch Stuck Open / Venting Problem
4 FLASHES
Status LED flashes four times; the furnace shuts down shortly after ignition and may retry several times.
Open High Limit Switch / Overtemperature
5 FLASHES
Status LED flashes five times; the furnace will not start the heating cycle.
Flame Sensed With Gas Valve Off (False Flame Signal)
6 FLASHES
Status LED flashes six times; the furnace locks out and will not heat.
Pressure Switch Cycle Fault / Intermittent Venting Issue
7 FLASHES
Status LED flashes seven times; the furnace attempts ignition but shuts down quickly.
Flame Loss During Operation
8 FLASHES
Status LED flashes eight times; the furnace will not start the heating cycle.
Ignitor Circuit Fault
9 FLASHES
Status LED flashes nine times; the blower may run continuously without heat.
Reversed Line Polarity or Grounding Issue
BLOWER FAULT (DISPLAY)
Display indicates a blower fault, no airflow, or intermittent airflow during a heat call.
Blower Motor or ECM Module Failure
LIMIT OPEN (DISPLAY)
The furnace display or diagnostic label indicates an open limit; the blower runs but the burners are off.
Open High Limit or Auxiliary Limit Switch
LOCKOUT (DISPLAY)
The control indicates ignition lockout; the furnace will not attempt to start until power is cycled.
Ignition Lockout After Repeated Failed Attempts
NO LED
No LED lights; the furnace is completely dead, with no blower or inducer operation.
No Power to Furnace / Failed Transformer or Control Board
PRESSURE SWITCH ERROR (DISPLAY)
Display shows a pressure switch error; the furnace will not ignite.
Pressure Switch or Venting Fault
STEADY ON
Status LED solid on with no flashing; the furnace is not responding to the thermostat.
Normal Power On / No Call for Heat or Board Locked
Symptom
Furnace blower starts and stops repeatedly without burner ignition.
Fan-Only Cycling / Control Logic Fault
Symptom
Furnace cabinet sweats or shows condensation on the outside.
Condensation / Humidity Issue
Symptom
Furnace causes frequent tripping of the circuit breaker.
Electrical Overload or Short Circuit
Symptom
Furnace cycles off on very cold days but runs normally in mild weather.
Marginal Venting or Combustion Air Problem
Symptom
Furnace ignites but the blower comes on very late, blowing very hot air and sometimes tripping the limit switch.
Blower On-Delay Control Problem
Symptom
Furnace runs but some rooms are too hot while others are too cold.
Air Distribution / Duct Imbalance
Symptom
Furnace runs but the carbon monoxide detector alarms when it operates.
Combustion / Venting Hazard
Symptom
Furnace shuts off and on when the blower speed changes or when another large appliance starts.
Voltage Drop / Electrical Interference
Symptom
Furnace starts then shuts off within a few seconds, repeating several times.
Flame Rollout or Safety Trip
Symptom
The blower runs continuously even when the thermostat is not calling for heat or fan.
Continuous Fan Operation
Symptom
The furnace is very noisy during operation (rattling, squealing, or grinding).
Mechanical Noise / Vibration
Symptom
The furnace makes a loud booming or banging noise at startup.
Delayed Ignition / Burner Light-Off Problem
Symptom
The furnace produces a strong burning or electrical smell when running.
Overheating Components or Electrical Overload
Symptom
The furnace runs but does not produce enough heat; the home never reaches the set temperature.
Underfiring or Insufficient Heat Output
Symptom
The furnace short cycles, turning on and off frequently without long run times.
Short Cycling
Symptom
The furnace will not start at all, but power and the LED are present.
No Call for Heat / Thermostat Circuit Fault
Symptom
Thermostat goes blank when the furnace tries to start.
Low-Voltage Short or Transformer Overload
Symptom
Water leaking around the base of the furnace or inside the cabinet.
Condensate Leak
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| 1 FLASH |
Status LED flashes once repeatedly, furnace will not start heating cycle
|
Ignition Failure / No Flame Detected | View Details |
| 2 FLASHES |
Status LED flashes twice repeatedly, furnace starts but shuts down shortly after ignition
|
Pressure Switch Stuck Closed | View Details |
| 3 FLASHES |
Status LED flashes three times, inducer runs but burners do not light
|
Pressure Switch Stuck Open / Venting Problem | View Details |
| 4 FLASHES |
Status LED flashes four times; the furnace shuts down shortly after ignition and may retry several times.
|
Open High Limit Switch / Overtemperature | View Details |
| 5 FLASHES |
Status LED flashes five times; the furnace will not start the heating cycle.
|
Flame Sensed With Gas Valve Off (False Flame Signal) | View Details |
| 6 FLASHES |
Status LED flashes six times; the furnace locks out and will not heat.
|
Pressure Switch Cycle Fault / Intermittent Venting Issue | View Details |
| 7 FLASHES |
Status LED flashes seven times; the furnace attempts ignition but shuts down quickly.
|
Flame Loss During Operation | View Details |
| 8 FLASHES |
Status LED flashes eight times; the furnace will not start the heating cycle.
|
Ignitor Circuit Fault | View Details |
| 9 FLASHES |
Status LED flashes nine times; the blower may run continuously without heat.
|
Reversed Line Polarity or Grounding Issue | View Details |
| BLOWER FAULT (DISPLAY) |
Display indicates a blower fault, no airflow, or intermittent airflow during a heat call.
|
Blower Motor or ECM Module Failure | View Details |
| LIMIT OPEN (DISPLAY) |
The furnace display or diagnostic label indicates an open limit; the blower runs but the burners are off.
|
Open High Limit or Auxiliary Limit Switch | View Details |
| LOCKOUT (DISPLAY) |
The control indicates ignition lockout; the furnace will not attempt to start until power is cycled.
|
Ignition Lockout After Repeated Failed Attempts | View Details |
| NO LED |
No LED lights; the furnace is completely dead, with no blower or inducer operation.
|
No Power to Furnace / Failed Transformer or Control Board | View Details |
| PRESSURE SWITCH ERROR (DISPLAY) |
Display shows a pressure switch error; the furnace will not ignite.
|
Pressure Switch or Venting Fault | View Details |
| STEADY ON |
Status LED solid on with no flashing; the furnace is not responding to the thermostat.
|
Normal Power On / No Call for Heat or Board Locked | View Details |
| – |
Furnace blower starts and stops repeatedly without burner ignition.
|
Fan-Only Cycling / Control Logic Fault | View Details |
| – |
Furnace cabinet sweats or shows condensation on the outside.
|
Condensation / Humidity Issue | View Details |
| – |
Furnace causes frequent tripping of the circuit breaker.
|
Electrical Overload or Short Circuit | View Details |
| – |
Furnace cycles off on very cold days but runs normally in mild weather.
|
Marginal Venting or Combustion Air Problem | View Details |
| – |
Furnace ignites but the blower comes on very late, blowing very hot air and sometimes tripping the limit switch.
|
Blower On-Delay Control Problem | View Details |
| – |
Furnace runs but some rooms are too hot while others are too cold.
|
Air Distribution / Duct Imbalance | View Details |
| – |
Furnace runs but the carbon monoxide detector alarms when it operates.
|
Combustion / Venting Hazard | View Details |
| – |
Furnace shuts off and on when the blower speed changes or when another large appliance starts.
|
Voltage Drop / Electrical Interference | View Details |
| – |
Furnace starts then shuts off within a few seconds, repeating several times.
|
Flame Rollout or Safety Trip | View Details |
| – |
The blower runs continuously even when the thermostat is not calling for heat or fan.
|
Continuous Fan Operation | View Details |
| – |
The furnace is very noisy during operation (rattling, squealing, or grinding).
|
Mechanical Noise / Vibration | View Details |
| – |
The furnace makes a loud booming or banging noise at startup.
|
Delayed Ignition / Burner Light-Off Problem | View Details |
| – |
The furnace produces a strong burning or electrical smell when running.
|
Overheating Components or Electrical Overload | View Details |
| – |
The furnace runs but does not produce enough heat; the home never reaches the set temperature.
|
Underfiring or Insufficient Heat Output | View Details |
| – |
The furnace short cycles, turning on and off frequently without long run times.
|
Short Cycling | View Details |
| – |
The furnace will not start at all, but power and the LED are present.
|
No Call for Heat / Thermostat Circuit Fault | View Details |
| – |
Thermostat goes blank when the furnace tries to start.
|
Low-Voltage Short or Transformer Overload | View Details |
| – |
Water leaking around the base of the furnace or inside the cabinet.
|
Condensate Leak | View Details |
No matching codes found
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