Westinghouse Furnaces Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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E1
Furnace will not start; thermostat is calling for heat but there is no inducer fan, no ignition attempt, and the control board shows E1.
Open or shorted return air temperature sensor circuit
E2
The furnace starts but shuts down quickly; the control board flashes or displays E2, and the blower may run continuously.
Supply air temperature sensor fault (open/shorted)
E3
The furnace attempts to start but locks out with E3; the inducer may run briefly, then stop, with no ignition.
Pressure switch failed to close
E4
The furnace starts the inducer and ignitor, the gas valve opens briefly, then shuts off with E4; multiple failed ignition attempts occur.
Flame not detected / flame sense failure
E5
The furnace locks out with E5 after ignition; burners light but shut off quickly, or the blower runs without heat.
Flame rollout or high-temperature limit trip
E6
The furnace displays E6 and will not start a heat cycle; the blower may run continuously.
High limit switch open / over-temperature condition
E7
The furnace shows E7; the inducer and blower may run unexpectedly or not at all; the thermostat appears unresponsive.
Thermostat communication or input fault
E8
The furnace displays E8 and will not run; this may occur after a power surge or wiring work.
Line voltage polarity or grounding error
E9
The furnace shows E9 and locks out; this may occur after repeated failed ignition or flame loss events.
Soft lockout due to repeated ignition failures
F01
The control board displays F01; the furnace may not respond to thermostat commands.
Internal control board fault
F02
The furnace shows F02, and the indoor blower does not run in heat or fan-only mode.
Blower motor fault / no blower operation
F03
Furnace displays F03; the inducer does not start when there is a call for heat.
Inducer motor fault / No draft
F04
Furnace displays F04; the blower runs but burners do not light, or the unit cycles off quickly.
Low flame signal / Marginal flame sensing
F05
Furnace displays F05 and shuts down; this may occur during blower ramp-up.
Blocked condensate or pressure-related fault
F06
Furnace displays F06; the blower may run at high speed continuously.
Limit circuit open or wiring fault
F07
Furnace displays F07; the inducer runs but there is no ignition attempt.
Ignition lockout / No ignitor operation
F08
Furnace displays F08; the gas valve does not open, and there is no flame, even though the ignitor glows.
Gas valve fault or no gas flow
F09
Furnace displays F09; the unit may short-cycle or fail to reach the set temperature.
Return air sensor out of range / Calibration error
F10
Furnace displays F10; the blower may run at a fixed speed regardless of thermostat commands.
ECM blower communication fault
Symptom
Furnace blower continues to run for a very long time after burners shut off, blowing cool air.
Blower off-delay or stuck fan relay
Symptom
Furnace ignites but produces yellow, lazy flames instead of sharp blue flames.
Improper combustion / incomplete burning
Symptom
Furnace inducer runs continuously even when there is no call for heat.
Stuck pressure switch or control logic fault
Symptom
Furnace makes a loud screeching or squealing noise when the blower runs.
Blower motor or belt noise (if belt-driven) / Bearing failure
Symptom
Furnace occasionally trips the household circuit breaker during operation.
Overcurrent or short circuit in furnace electrical system
Symptom
Furnace will not start at all; no blower, no inducer, no lights on the control board.
No power to the furnace
Symptom
The furnace blower runs, but there is a strong burning or electrical smell from the vents.
Overheating blower motor or electrical component
Symptom
The furnace cycles on and off rapidly (every 1–5 minutes) without maintaining temperature.
Thermostat or control short cycling
Symptom
The furnace makes loud banging or booming noises at startup.
Delayed ignition / burner light-off problem
Symptom
The furnace produces a high-pitched whistling or howling noise during operation.
Airflow restriction or duct resonance
Symptom
The furnace runs but produces no heat; the blower runs continuously with room temperature air.
No burner ignition with continuous blower operation
Symptom
The furnace runs, but some rooms are too cold while others are too warm.
Uneven heating / airflow imbalance
Symptom
The furnace runs, but the carbon monoxide detector in the home activates during operation.
Combustion or venting failure
Symptom
The furnace short cycles: it starts, runs for a few minutes, then shuts off before reaching the thermostat setpoint, repeating frequently.
Overheating and high limit cycling
Symptom
The furnace starts but shuts down as soon as the blower comes on.
Flame disturbance or pressure issue when the blower starts
Symptom
The furnace vibrates excessively and causes rattling noises in the ductwork.
Mechanical vibration from the blower or inducer
Symptom
The furnace will not start when the thermostat calls for heat, but fan-only mode works.
Heat call not reaching the furnace control
Symptom
Water leaking around the base of the furnace or onto the nearby floor.
Condensate leakage from a high-efficiency furnace
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E1 |
Furnace will not start; thermostat is calling for heat but there is no inducer fan, no ignition attempt, and the control board shows E1.
|
Open or shorted return air temperature sensor circuit | View Details |
| E2 |
The furnace starts but shuts down quickly; the control board flashes or displays E2, and the blower may run continuously.
|
Supply air temperature sensor fault (open/shorted) | View Details |
| E3 |
The furnace attempts to start but locks out with E3; the inducer may run briefly, then stop, with no ignition.
|
Pressure switch failed to close | View Details |
| E4 |
The furnace starts the inducer and ignitor, the gas valve opens briefly, then shuts off with E4; multiple failed ignition attempts occur.
|
Flame not detected / flame sense failure | View Details |
| E5 |
The furnace locks out with E5 after ignition; burners light but shut off quickly, or the blower runs without heat.
|
Flame rollout or high-temperature limit trip | View Details |
| E6 |
The furnace displays E6 and will not start a heat cycle; the blower may run continuously.
|
High limit switch open / over-temperature condition | View Details |
| E7 |
The furnace shows E7; the inducer and blower may run unexpectedly or not at all; the thermostat appears unresponsive.
|
Thermostat communication or input fault | View Details |
| E8 |
The furnace displays E8 and will not run; this may occur after a power surge or wiring work.
|
Line voltage polarity or grounding error | View Details |
| E9 |
The furnace shows E9 and locks out; this may occur after repeated failed ignition or flame loss events.
|
Soft lockout due to repeated ignition failures | View Details |
| F01 |
The control board displays F01; the furnace may not respond to thermostat commands.
|
Internal control board fault | View Details |
| F02 |
The furnace shows F02, and the indoor blower does not run in heat or fan-only mode.
|
Blower motor fault / no blower operation | View Details |
| F03 |
Furnace displays F03; the inducer does not start when there is a call for heat.
|
Inducer motor fault / No draft | View Details |
| F04 |
Furnace displays F04; the blower runs but burners do not light, or the unit cycles off quickly.
|
Low flame signal / Marginal flame sensing | View Details |
| F05 |
Furnace displays F05 and shuts down; this may occur during blower ramp-up.
|
Blocked condensate or pressure-related fault | View Details |
| F06 |
Furnace displays F06; the blower may run at high speed continuously.
|
Limit circuit open or wiring fault | View Details |
| F07 |
Furnace displays F07; the inducer runs but there is no ignition attempt.
|
Ignition lockout / No ignitor operation | View Details |
| F08 |
Furnace displays F08; the gas valve does not open, and there is no flame, even though the ignitor glows.
|
Gas valve fault or no gas flow | View Details |
| F09 |
Furnace displays F09; the unit may short-cycle or fail to reach the set temperature.
|
Return air sensor out of range / Calibration error | View Details |
| F10 |
Furnace displays F10; the blower may run at a fixed speed regardless of thermostat commands.
|
ECM blower communication fault | View Details |
| – |
Furnace blower continues to run for a very long time after burners shut off, blowing cool air.
|
Blower off-delay or stuck fan relay | View Details |
| – |
Furnace ignites but produces yellow, lazy flames instead of sharp blue flames.
|
Improper combustion / incomplete burning | View Details |
| – |
Furnace inducer runs continuously even when there is no call for heat.
|
Stuck pressure switch or control logic fault | View Details |
| – |
Furnace makes a loud screeching or squealing noise when the blower runs.
|
Blower motor or belt noise (if belt-driven) / Bearing failure | View Details |
| – |
Furnace occasionally trips the household circuit breaker during operation.
|
Overcurrent or short circuit in furnace electrical system | View Details |
| – |
Furnace will not start at all; no blower, no inducer, no lights on the control board.
|
No power to the furnace | View Details |
| – |
The furnace blower runs, but there is a strong burning or electrical smell from the vents.
|
Overheating blower motor or electrical component | View Details |
| – |
The furnace cycles on and off rapidly (every 1–5 minutes) without maintaining temperature.
|
Thermostat or control short cycling | View Details |
| – |
The furnace makes loud banging or booming noises at startup.
|
Delayed ignition / burner light-off problem | View Details |
| – |
The furnace produces a high-pitched whistling or howling noise during operation.
|
Airflow restriction or duct resonance | View Details |
| – |
The furnace runs but produces no heat; the blower runs continuously with room temperature air.
|
No burner ignition with continuous blower operation | View Details |
| – |
The furnace runs, but some rooms are too cold while others are too warm.
|
Uneven heating / airflow imbalance | View Details |
| – |
The furnace runs, but the carbon monoxide detector in the home activates during operation.
|
Combustion or venting failure | View Details |
| – |
The furnace short cycles: it starts, runs for a few minutes, then shuts off before reaching the thermostat setpoint, repeating frequently.
|
Overheating and high limit cycling | View Details |
| – |
The furnace starts but shuts down as soon as the blower comes on.
|
Flame disturbance or pressure issue when the blower starts | View Details |
| – |
The furnace vibrates excessively and causes rattling noises in the ductwork.
|
Mechanical vibration from the blower or inducer | View Details |
| – |
The furnace will not start when the thermostat calls for heat, but fan-only mode works.
|
Heat call not reaching the furnace control | View Details |
| – |
Water leaking around the base of the furnace or onto the nearby floor.
|
Condensate leakage from a high-efficiency furnace | View Details |
No matching codes found
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