Napoleon
Napoleon Furnaces Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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E01
Furnace will not start; control board shows E01 and inducer motor does not run
Pressure Switch Failed to Close on Call for Heat
E02
Furnace attempts to start but shuts down with E02; inducer runs but no ignition
Flame Not Detected / Ignition Failure
E03
Furnace starts, burners light briefly, then shut off with E03 code
Flame Loss During Run
E04
Furnace displays E04 and shuts down shortly after blower starts
High Limit Switch Open (Overtemperature)
E05
Furnace shows E05 and will not complete ignition sequence; inducer may start and stop repeatedly
Pressure Switch Stuck Open or Failed to Prove Draft
E06
Control board displays E06; furnace shuts down and may lock out after several attempts
Rollout Switch Open / Flame Rollout Detected
E07
Furnace displays E07 and blower runs continuously without heat
Low Limit / Fan Limit or Auxiliary Limit Open
E08
Furnace shows E08; inducer and blower may not run; no response to thermostat
24V Control Circuit Low Voltage or Short
E09
Furnace displays E09 and will not respond to thermostat commands
Internal Control Board Fault / EEPROM Error
E10
Furnace shows E10; inducer may start but burners do not light; may indicate reversed polarity or grounding issue
Line Voltage Polarity / Ground Fault
E11
Furnace displays E11; inducer runs continuously without ignition attempts
Stuck Closed Pressure Switch
E12
Furnace shows E12; blower may start but burners do not ignite; often associated with limit circuit issues
Open Limit Circuit Lockout
E13
Furnace displays E13; burners light but main blower does not start, then unit overheats and shuts down
Blower Motor Failure or Fan Relay Fault
E14
Furnace shows E14; inducer does not start; no ignition attempts
Inducer Motor Failure or Inducer Relay Fault
E15
Furnace displays E15; burners ignite but shut off quickly; may indicate improper flame sensing or polarity
Flame Sense Polarity / Microamp Signal Fault
E16
Furnace shows E16; unit may lock out after multiple failed ignition attempts
Ignition Lockout (Exceeded Retry Limit)
E17
Furnace displays E17; blower runs at high speed continuously, no heat
Emergency Heat / Fault Mode – Limit or Board Failure
E18
Furnace shows E18; unit may operate but with abnormal fan behavior or intermittent shutdowns
ECM Blower Communication Error
E19
Furnace displays E19; unit may shut down on condensate-related fault
Condensate Overflow or Float Switch Open
E20
Furnace shows E20; unit may not respond to thermostat or behaves erratically
Thermostat Input Error
Symptom
Furnace blower runs continuously even when thermostat is not calling for heat
Continuous Fan Operation
Symptom
Furnace causes a rotten egg or sulfur smell in the home
Gas Leak or Combustion Problem
Symptom
Furnace cycles on and off rapidly (every 1–5 minutes) without reaching temperature
Rapid Cycling Due to Thermostat or Flame Sensing Issues
Symptom
Furnace emits a burning smell when running
Overheating Components or Dust Burn-Off
Symptom
Furnace frequently trips the household circuit breaker
Electrical Overload or Short Circuit
Symptom
Furnace inducer runs but burners never ignite; no error code displayed
Silent Ignition Failure
Symptom
Furnace makes loud banging or booming noise at startup
Delayed Ignition / Burner Light-Off Problem
Symptom
Furnace produces a high-pitched whine or loud humming during operation
Blower or Inducer Mechanical Noise
Symptom
Furnace runs but carbon monoxide detector in home alarms
Unsafe Combustion / Flue Gas Spillage
Symptom
Furnace runs but does not produce enough heat; home never reaches set temperature
Underfiring or Insufficient Heat Output
Symptom
Furnace runs but some rooms are much colder than others
Uneven Heating / Airflow Imbalance
Symptom
Furnace short cycles: starts, runs for a few minutes, then shuts off and restarts frequently
Short Cycling Due to Overheating or Thermostat Issues
Symptom
Furnace starts normally but shuts off when blower starts
Flame Disturbance Due to Airflow
Symptom
Furnace vibrates excessively and causes rattling in ductwork
Excessive Vibration / Imbalanced Blower Wheel
Symptom
Furnace will not start at all; no inducer, no blower, no lights on control board
No Power to Furnace
Symptom
Thermostat calls for heat but furnace only clicks and never starts inducer or blower
Control Board Relay or Low-Voltage Control Fault
Symptom
Visible rust flakes or corrosion inside furnace cabinet and on burners
Corrosion Due to Condensate or Combustion Issues
Symptom
Water pooling around the base of the furnace
Condensate Leak
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E01 |
Furnace will not start; control board shows E01 and inducer motor does not run
|
Pressure Switch Failed to Close on Call for Heat | View Details |
| E02 |
Furnace attempts to start but shuts down with E02; inducer runs but no ignition
|
Flame Not Detected / Ignition Failure | View Details |
| E03 |
Furnace starts, burners light briefly, then shut off with E03 code
|
Flame Loss During Run | View Details |
| E04 |
Furnace displays E04 and shuts down shortly after blower starts
|
High Limit Switch Open (Overtemperature) | View Details |
| E05 |
Furnace shows E05 and will not complete ignition sequence; inducer may start and stop repeatedly
|
Pressure Switch Stuck Open or Failed to Prove Draft | View Details |
| E06 |
Control board displays E06; furnace shuts down and may lock out after several attempts
|
Rollout Switch Open / Flame Rollout Detected | View Details |
| E07 |
Furnace displays E07 and blower runs continuously without heat
|
Low Limit / Fan Limit or Auxiliary Limit Open | View Details |
| E08 |
Furnace shows E08; inducer and blower may not run; no response to thermostat
|
24V Control Circuit Low Voltage or Short | View Details |
| E09 |
Furnace displays E09 and will not respond to thermostat commands
|
Internal Control Board Fault / EEPROM Error | View Details |
| E10 |
Furnace shows E10; inducer may start but burners do not light; may indicate reversed polarity or grounding issue
|
Line Voltage Polarity / Ground Fault | View Details |
| E11 |
Furnace displays E11; inducer runs continuously without ignition attempts
|
Stuck Closed Pressure Switch | View Details |
| E12 |
Furnace shows E12; blower may start but burners do not ignite; often associated with limit circuit issues
|
Open Limit Circuit Lockout | View Details |
| E13 |
Furnace displays E13; burners light but main blower does not start, then unit overheats and shuts down
|
Blower Motor Failure or Fan Relay Fault | View Details |
| E14 |
Furnace shows E14; inducer does not start; no ignition attempts
|
Inducer Motor Failure or Inducer Relay Fault | View Details |
| E15 |
Furnace displays E15; burners ignite but shut off quickly; may indicate improper flame sensing or polarity
|
Flame Sense Polarity / Microamp Signal Fault | View Details |
| E16 |
Furnace shows E16; unit may lock out after multiple failed ignition attempts
|
Ignition Lockout (Exceeded Retry Limit) | View Details |
| E17 |
Furnace displays E17; blower runs at high speed continuously, no heat
|
Emergency Heat / Fault Mode – Limit or Board Failure | View Details |
| E18 |
Furnace shows E18; unit may operate but with abnormal fan behavior or intermittent shutdowns
|
ECM Blower Communication Error | View Details |
| E19 |
Furnace displays E19; unit may shut down on condensate-related fault
|
Condensate Overflow or Float Switch Open | View Details |
| E20 |
Furnace shows E20; unit may not respond to thermostat or behaves erratically
|
Thermostat Input Error | View Details |
| – |
Furnace blower runs continuously even when thermostat is not calling for heat
|
Continuous Fan Operation | View Details |
| – |
Furnace causes a rotten egg or sulfur smell in the home
|
Gas Leak or Combustion Problem | View Details |
| – |
Furnace cycles on and off rapidly (every 1–5 minutes) without reaching temperature
|
Rapid Cycling Due to Thermostat or Flame Sensing Issues | View Details |
| – |
Furnace emits a burning smell when running
|
Overheating Components or Dust Burn-Off | View Details |
| – |
Furnace frequently trips the household circuit breaker
|
Electrical Overload or Short Circuit | View Details |
| – |
Furnace inducer runs but burners never ignite; no error code displayed
|
Silent Ignition Failure | View Details |
| – |
Furnace makes loud banging or booming noise at startup
|
Delayed Ignition / Burner Light-Off Problem | View Details |
| – |
Furnace produces a high-pitched whine or loud humming during operation
|
Blower or Inducer Mechanical Noise | View Details |
| – |
Furnace runs but carbon monoxide detector in home alarms
|
Unsafe Combustion / Flue Gas Spillage | View Details |
| – |
Furnace runs but does not produce enough heat; home never reaches set temperature
|
Underfiring or Insufficient Heat Output | View Details |
| – |
Furnace runs but some rooms are much colder than others
|
Uneven Heating / Airflow Imbalance | View Details |
| – |
Furnace short cycles: starts, runs for a few minutes, then shuts off and restarts frequently
|
Short Cycling Due to Overheating or Thermostat Issues | View Details |
| – |
Furnace starts normally but shuts off when blower starts
|
Flame Disturbance Due to Airflow | View Details |
| – |
Furnace vibrates excessively and causes rattling in ductwork
|
Excessive Vibration / Imbalanced Blower Wheel | View Details |
| – |
Furnace will not start at all; no inducer, no blower, no lights on control board
|
No Power to Furnace | View Details |
| – |
Thermostat calls for heat but furnace only clicks and never starts inducer or blower
|
Control Board Relay or Low-Voltage Control Fault | View Details |
| – |
Visible rust flakes or corrosion inside furnace cabinet and on burners
|
Corrosion Due to Condensate or Combustion Issues | View Details |
| – |
Water pooling around the base of the furnace
|
Condensate Leak | View Details |
No matching codes found
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