Navien
Navien Furnaces Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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E001
Navien furnace will not fire, the display shows E001, and the burner never lights.
Low Water Pressure / Flow Fault
E002
Navien furnace locks out with E002; the unit attempts to start but shuts down quickly.
Low Water Level / Flow Switch Fault
E003
Navien furnace shows E003 and will not ignite; the fan may run briefly then stop.
Ignition Failure / Flame Not Detected
E004
Navien furnace displays E004; the unit shuts down shortly after an ignition attempt.
Flame Loss During Operation
E010
Navien furnace shows E010 and shuts down; the fan may run at high speed.
Abnormal Air Pressure / Fan Motor Fault
E012
Navien furnace displays E012; the unit will not run, sometimes after heavy rain or snow.
Flue Blockage / Exhaust Restriction
E016
Navien furnace shows E016 and shuts down during operation, often after running for a while.
Overheating / High Limit Trip
E021
Navien furnace displays E021; the unit will not start the heating cycle.
Thermistor (Temperature Sensor) Fault
E022
Navien furnace shows E022; the unit may start but quickly shuts down.
Return Water Thermistor Fault
E027
Navien furnace intermittently shuts down with E027, especially during long runs.
Exhaust Overheat / Flue Gas Temperature Fault
E030
Navien furnace shows E030 and will not operate, often after power issues.
Internal Control Communication Error
E046
Navien furnace displays E046; the unit may run at reduced capacity or shut down.
Outdoor Temperature Sensor Fault (for systems using outdoor reset)
E051
Navien furnace shows E051; heating demand is not recognized, or the unit does not respond to the thermostat.
Thermostat / Room Controller Communication Fault
E060
Navien furnace displays E060; the unit may not modulate correctly or may shut down.
Gas Valve Modulation / Valve Drive Fault
E109
Navien furnace shows E109; the unit may not start or may shut down unexpectedly.
Internal Fan / Blower Speed Feedback Fault
E110
Navien furnace displays E110; the unit locks out and will not restart.
Flame Detection Circuit Fault
E127
Navien furnace intermittently shows E127, especially during very cold weather.
Condensate Drain / Trap Fault
E203
Navien furnace shows E203; the unit does not respond to zone calls properly.
Zone Control / Internal Pump Control Fault
E302
Navien furnace displays E302; the unit may not start after a power outage.
EEPROM / Configuration Data Error
Symptom
Navien furnace cabinet vibrates excessively during operation.
Mechanical Vibration / Imbalanced Fan
Symptom
Navien furnace display is blank and the unit is completely unresponsive.
No Power / Control Failure
Symptom
Navien furnace display shows fluctuating or incorrect water temperature readings.
Erratic Temperature Sensing
Symptom
Navien furnace display shows normal operation, but the house is overheating.
Overheating Space / Control Misconfiguration
Symptom
Navien furnace emits a strong exhaust or burning smell near the unit or vent termination.
Combustion Odor / Incomplete Combustion
Symptom
Navien furnace fan runs, but the burner does not light, and no error code is displayed.
No Heat / Ignition Sequence Not Completing
Symptom
Navien furnace frequently loses pressure and requires frequent refilling.
Chronic Pressure Loss / System Leak
Symptom
Navien furnace frequently trips the household breaker.
Electrical Overload / Short Circuit
Symptom
Navien furnace is very noisy during operation, with rumbling or roaring sounds from the burner area.
Combustion Noise / Burner Instability
Symptom
Navien furnace locks out occasionally during very cold weather without a clear error code; the outdoor unit or piping appears frosted.
Freeze Protection / Low Temperature Lockout
Symptom
Navien furnace makes loud banging or knocking noises in the piping when the burner fires or shuts off.
Water Hammer / Thermal Expansion Noise
Symptom
Navien furnace produces gurgling or trickling water sounds inside the unit.
Air in Heat Exchanger / Condensate Flow Noise
Symptom
Navien furnace runs but does not provide enough heat to the home; supply water temperature is lower than expected.
Underheating / Insufficient BTU Output
Symptom
Navien furnace runs, but some zones or radiators stay cold.
Zone Flow Imbalance / Airbound Zones
Symptom
Navien furnace short cycles: it frequently turns on and off with very short run times.
Short Cycling / Oversized Boiler or Control Misconfiguration
Symptom
Water leaking from the bottom of the Navien furnace cabinet.
Internal Water Leak
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E001 |
Navien furnace will not fire, the display shows E001, and the burner never lights.
|
Low Water Pressure / Flow Fault | View Details |
| E002 |
Navien furnace locks out with E002; the unit attempts to start but shuts down quickly.
|
Low Water Level / Flow Switch Fault | View Details |
| E003 |
Navien furnace shows E003 and will not ignite; the fan may run briefly then stop.
|
Ignition Failure / Flame Not Detected | View Details |
| E004 |
Navien furnace displays E004; the unit shuts down shortly after an ignition attempt.
|
Flame Loss During Operation | View Details |
| E010 |
Navien furnace shows E010 and shuts down; the fan may run at high speed.
|
Abnormal Air Pressure / Fan Motor Fault | View Details |
| E012 |
Navien furnace displays E012; the unit will not run, sometimes after heavy rain or snow.
|
Flue Blockage / Exhaust Restriction | View Details |
| E016 |
Navien furnace shows E016 and shuts down during operation, often after running for a while.
|
Overheating / High Limit Trip | View Details |
| E021 |
Navien furnace displays E021; the unit will not start the heating cycle.
|
Thermistor (Temperature Sensor) Fault | View Details |
| E022 |
Navien furnace shows E022; the unit may start but quickly shuts down.
|
Return Water Thermistor Fault | View Details |
| E027 |
Navien furnace intermittently shuts down with E027, especially during long runs.
|
Exhaust Overheat / Flue Gas Temperature Fault | View Details |
| E030 |
Navien furnace shows E030 and will not operate, often after power issues.
|
Internal Control Communication Error | View Details |
| E046 |
Navien furnace displays E046; the unit may run at reduced capacity or shut down.
|
Outdoor Temperature Sensor Fault (for systems using outdoor reset) | View Details |
| E051 |
Navien furnace shows E051; heating demand is not recognized, or the unit does not respond to the thermostat.
|
Thermostat / Room Controller Communication Fault | View Details |
| E060 |
Navien furnace displays E060; the unit may not modulate correctly or may shut down.
|
Gas Valve Modulation / Valve Drive Fault | View Details |
| E109 |
Navien furnace shows E109; the unit may not start or may shut down unexpectedly.
|
Internal Fan / Blower Speed Feedback Fault | View Details |
| E110 |
Navien furnace displays E110; the unit locks out and will not restart.
|
Flame Detection Circuit Fault | View Details |
| E127 |
Navien furnace intermittently shows E127, especially during very cold weather.
|
Condensate Drain / Trap Fault | View Details |
| E203 |
Navien furnace shows E203; the unit does not respond to zone calls properly.
|
Zone Control / Internal Pump Control Fault | View Details |
| E302 |
Navien furnace displays E302; the unit may not start after a power outage.
|
EEPROM / Configuration Data Error | View Details |
| – |
Navien furnace cabinet vibrates excessively during operation.
|
Mechanical Vibration / Imbalanced Fan | View Details |
| – |
Navien furnace display is blank and the unit is completely unresponsive.
|
No Power / Control Failure | View Details |
| – |
Navien furnace display shows fluctuating or incorrect water temperature readings.
|
Erratic Temperature Sensing | View Details |
| – |
Navien furnace display shows normal operation, but the house is overheating.
|
Overheating Space / Control Misconfiguration | View Details |
| – |
Navien furnace emits a strong exhaust or burning smell near the unit or vent termination.
|
Combustion Odor / Incomplete Combustion | View Details |
| – |
Navien furnace fan runs, but the burner does not light, and no error code is displayed.
|
No Heat / Ignition Sequence Not Completing | View Details |
| – |
Navien furnace frequently loses pressure and requires frequent refilling.
|
Chronic Pressure Loss / System Leak | View Details |
| – |
Navien furnace frequently trips the household breaker.
|
Electrical Overload / Short Circuit | View Details |
| – |
Navien furnace is very noisy during operation, with rumbling or roaring sounds from the burner area.
|
Combustion Noise / Burner Instability | View Details |
| – |
Navien furnace locks out occasionally during very cold weather without a clear error code; the outdoor unit or piping appears frosted.
|
Freeze Protection / Low Temperature Lockout | View Details |
| – |
Navien furnace makes loud banging or knocking noises in the piping when the burner fires or shuts off.
|
Water Hammer / Thermal Expansion Noise | View Details |
| – |
Navien furnace produces gurgling or trickling water sounds inside the unit.
|
Air in Heat Exchanger / Condensate Flow Noise | View Details |
| – |
Navien furnace runs but does not provide enough heat to the home; supply water temperature is lower than expected.
|
Underheating / Insufficient BTU Output | View Details |
| – |
Navien furnace runs, but some zones or radiators stay cold.
|
Zone Flow Imbalance / Airbound Zones | View Details |
| – |
Navien furnace short cycles: it frequently turns on and off with very short run times.
|
Short Cycling / Oversized Boiler or Control Misconfiguration | View Details |
| – |
Water leaking from the bottom of the Navien furnace cabinet.
|
Internal Water Leak | View Details |
No matching codes found
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