Tempstar
Tempstar Furnaces Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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11
Furnace control board LED flashes 1 short and 1 long (code 11); furnace will not start a heat cycle.
No Previous Code / Control Power Interruption
12
Control board LED flashes code 12; blower runs briefly after power-up, but no heat call is processed.
Blower On After Power-Up / Normal Initialization
13
LED flashes code 13; furnace locks out and will not restart for about 3 hours unless power is cycled.
Limit Switch Lockout / Flame Rollout or High-Temperature Lockout
14
LED flashes code 14; furnace attempts ignition but locks out after failed ignition attempts.
Ignition Lockout
21
Control board LED flashes code 21; furnace stops mid-cycle or will not start a new cycle.
Gas Heating Lockout (Retries or Recycles Exceeded)
22
LED flashes code 22; furnace will not start heating cycle, inducer may not run.
Abnormal Flame-Proving Signal / Flame Detected with Gas Off
23
Control board LED flashes code 23; furnace may start but shuts down unexpectedly or will not start.
Pressure Switch Did Not Open or Close Properly
24
LED flashes code 24; thermostat calls are not recognized, furnace does not respond to heat demand.
Open or Shorted Secondary (24V) Circuit
31
LED flashes code 31; inducer may run but furnace will not ignite, or shuts down shortly after starting.
Pressure, Draft, or Airflow Fault
32
LED flashes code 32; furnace may start but shuts down on limit, blower may run continuously.
Open High Limit Switch
33
LED flashes code 33; blower runs continuously, burners do not fire.
Limit or Flame Rollout Switch Open
34
LED flashes code 34; ignitor glows but burners do not light, or light briefly then go out.
Ignition Proving Failure
41
LED flashes code 41; blower runs at incorrect speed or airflow seems low/high compared to normal.
Blower Motor Fault / Incorrect Blower Operation
42
LED flashes code 42; inducer or outdoor unit may not respond correctly, furnace may short-cycle.
Inducer or Outdoor Unit Fault (Communication/Control)
43
LED flashes code 43; furnace may not respond correctly to thermostat calls, staging may be incorrect on two-stage Tempstar models.
Control Board or Communication Fault
44
LED flashes code 44; furnace may shut down unexpectedly or not start, often associated with flame sensing issues.
Flame Sensing Circuit Fault
45
LED flashes code 45; furnace locks out and may require power cycling to restart.
Control Board Internal Fault / Repeated Lockouts
E0
Tempstar communicating furnace thermostat or interface displays E0; system not responding to commands.
Communication Loss Between Thermostat and Furnace
E1
Tempstar communicating thermostat shows E1; furnace may not respond or may run in backup mode.
Indoor Unit Communication Error
Symptom
Blower runs continuously even when thermostat is not calling for heat or fan.
Stuck Blower Relay or Open Limit Switch
Symptom
Burners light but go out after a few seconds; furnace repeatedly tries to ignite and then shuts down.
Flame Sensing Failure
Symptom
Furnace cycles on and off rapidly (every 1–5 minutes) without reaching temperature; thermostat clicks frequently.
Thermostat or Control Cycling Issue
Symptom
Furnace frequently trips the household circuit breaker.
Electrical Overload or Short Circuit
Symptom
Furnace ignites but produces yellow, lazy, or lifting flames.
Improper Combustion
Symptom
Furnace makes loud booming or delayed ignition noise when burners light.
Delayed Ignition
Symptom
Furnace or nearby area smells like burning dust at the start of the heating season.
Dust Burn-Off
Symptom
Furnace produces a high-pitched whine or rumbling noise during operation.
Inducer or Blower Noise
Symptom
Furnace runs but delivers insufficient heat; home never reaches set temperature.
Low Heat Output
Symptom
Furnace runs but some rooms are too hot while others are too cold.
Uneven Heating / Air Distribution Problem
Symptom
Furnace starts and runs for a few minutes, then shuts off and restarts frequently (short cycling).
Short Cycling Due to Overheating or Control Issues
Symptom
Furnace starts normally but shuts off on very cold or very windy days.
Weather-Related Venting or Combustion Issue
Symptom
Furnace vibrates excessively or rattles during operation.
Mechanical Vibration
Symptom
Furnace will not start at all; no blower, no inducer, no LED lights on Tempstar control board.
No Power to Furnace
Symptom
Inducer motor runs but burners never light; you hear clicking or see ignitor glow, but no flame.
No Gas Ignition
Symptom
Strong metallic, electrical, or plastic burning smell from furnace during operation.
Electrical Overheating or Component Failure
Symptom
Thermostat calls for heat but furnace only runs the inducer or cycles without producing warm air.
Partial Heating Cycle / Incomplete Ignition Sequence
Symptom
Thermostat display is blank and furnace does not run.
Loss of 24V Control Power to Thermostat
Symptom
Water dripping from metal flue pipe on a standard-efficiency Tempstar furnace.
Flue Condensation
Symptom
Water leaking around the base of a high-efficiency Tempstar furnace.
Condensate Leak
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| 11 |
Furnace control board LED flashes 1 short and 1 long (code 11); furnace will not start a heat cycle.
|
No Previous Code / Control Power Interruption | View Details |
| 12 |
Control board LED flashes code 12; blower runs briefly after power-up, but no heat call is processed.
|
Blower On After Power-Up / Normal Initialization | View Details |
| 13 |
LED flashes code 13; furnace locks out and will not restart for about 3 hours unless power is cycled.
|
Limit Switch Lockout / Flame Rollout or High-Temperature Lockout | View Details |
| 14 |
LED flashes code 14; furnace attempts ignition but locks out after failed ignition attempts.
|
Ignition Lockout | View Details |
| 21 |
Control board LED flashes code 21; furnace stops mid-cycle or will not start a new cycle.
|
Gas Heating Lockout (Retries or Recycles Exceeded) | View Details |
| 22 |
LED flashes code 22; furnace will not start heating cycle, inducer may not run.
|
Abnormal Flame-Proving Signal / Flame Detected with Gas Off | View Details |
| 23 |
Control board LED flashes code 23; furnace may start but shuts down unexpectedly or will not start.
|
Pressure Switch Did Not Open or Close Properly | View Details |
| 24 |
LED flashes code 24; thermostat calls are not recognized, furnace does not respond to heat demand.
|
Open or Shorted Secondary (24V) Circuit | View Details |
| 31 |
LED flashes code 31; inducer may run but furnace will not ignite, or shuts down shortly after starting.
|
Pressure, Draft, or Airflow Fault | View Details |
| 32 |
LED flashes code 32; furnace may start but shuts down on limit, blower may run continuously.
|
Open High Limit Switch | View Details |
| 33 |
LED flashes code 33; blower runs continuously, burners do not fire.
|
Limit or Flame Rollout Switch Open | View Details |
| 34 |
LED flashes code 34; ignitor glows but burners do not light, or light briefly then go out.
|
Ignition Proving Failure | View Details |
| 41 |
LED flashes code 41; blower runs at incorrect speed or airflow seems low/high compared to normal.
|
Blower Motor Fault / Incorrect Blower Operation | View Details |
| 42 |
LED flashes code 42; inducer or outdoor unit may not respond correctly, furnace may short-cycle.
|
Inducer or Outdoor Unit Fault (Communication/Control) | View Details |
| 43 |
LED flashes code 43; furnace may not respond correctly to thermostat calls, staging may be incorrect on two-stage Tempstar models.
|
Control Board or Communication Fault | View Details |
| 44 |
LED flashes code 44; furnace may shut down unexpectedly or not start, often associated with flame sensing issues.
|
Flame Sensing Circuit Fault | View Details |
| 45 |
LED flashes code 45; furnace locks out and may require power cycling to restart.
|
Control Board Internal Fault / Repeated Lockouts | View Details |
| E0 |
Tempstar communicating furnace thermostat or interface displays E0; system not responding to commands.
|
Communication Loss Between Thermostat and Furnace | View Details |
| E1 |
Tempstar communicating thermostat shows E1; furnace may not respond or may run in backup mode.
|
Indoor Unit Communication Error | View Details |
| – |
Blower runs continuously even when thermostat is not calling for heat or fan.
|
Stuck Blower Relay or Open Limit Switch | View Details |
| – |
Burners light but go out after a few seconds; furnace repeatedly tries to ignite and then shuts down.
|
Flame Sensing Failure | View Details |
| – |
Furnace cycles on and off rapidly (every 1–5 minutes) without reaching temperature; thermostat clicks frequently.
|
Thermostat or Control Cycling Issue | View Details |
| – |
Furnace frequently trips the household circuit breaker.
|
Electrical Overload or Short Circuit | View Details |
| – |
Furnace ignites but produces yellow, lazy, or lifting flames.
|
Improper Combustion | View Details |
| – |
Furnace makes loud booming or delayed ignition noise when burners light.
|
Delayed Ignition | View Details |
| – |
Furnace or nearby area smells like burning dust at the start of the heating season.
|
Dust Burn-Off | View Details |
| – |
Furnace produces a high-pitched whine or rumbling noise during operation.
|
Inducer or Blower Noise | View Details |
| – |
Furnace runs but delivers insufficient heat; home never reaches set temperature.
|
Low Heat Output | View Details |
| – |
Furnace runs but some rooms are too hot while others are too cold.
|
Uneven Heating / Air Distribution Problem | View Details |
| – |
Furnace starts and runs for a few minutes, then shuts off and restarts frequently (short cycling).
|
Short Cycling Due to Overheating or Control Issues | View Details |
| – |
Furnace starts normally but shuts off on very cold or very windy days.
|
Weather-Related Venting or Combustion Issue | View Details |
| – |
Furnace vibrates excessively or rattles during operation.
|
Mechanical Vibration | View Details |
| – |
Furnace will not start at all; no blower, no inducer, no LED lights on Tempstar control board.
|
No Power to Furnace | View Details |
| – |
Inducer motor runs but burners never light; you hear clicking or see ignitor glow, but no flame.
|
No Gas Ignition | View Details |
| – |
Strong metallic, electrical, or plastic burning smell from furnace during operation.
|
Electrical Overheating or Component Failure | View Details |
| – |
Thermostat calls for heat but furnace only runs the inducer or cycles without producing warm air.
|
Partial Heating Cycle / Incomplete Ignition Sequence | View Details |
| – |
Thermostat display is blank and furnace does not run.
|
Loss of 24V Control Power to Thermostat | View Details |
| – |
Water dripping from metal flue pipe on a standard-efficiency Tempstar furnace.
|
Flue Condensation | View Details |
| – |
Water leaking around the base of a high-efficiency Tempstar furnace.
|
Condensate Leak | View Details |
No matching codes found
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