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