Baxi 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 fails to ignite, burner does not light, ignition sequence aborts after a few attempts.
Ignition Lockout
E02
Furnace locks out shortly after ignition; the burner lights briefly, then shuts down.
Flame Detection Failure
E03
Furnace attempts to start but shuts down with the fan running; no ignition occurs, and the flue fan may cycle.
Flue Fan / Air Pressure Switch Fault
E04
Furnace shuts down with an overheat indication; the flow temperature rises rapidly, then the burner cuts out.
Primary Heat Exchanger Overheat / High Limit Trip
E05
Furnace displays a flow temperature sensor fault; it may not start or may run erratically.
Flow NTC Sensor Failure
E06
Furnace shows a return temperature sensor fault; it may short-cycle or lock out.
Return NTC Sensor Failure
E07
Furnace indicates a flue gas sensor or flue thermostat fault; it may shut down during operation.
Flue Temperature Sensor / Thermostat Trip
E08
Furnace shows low water pressure or a water pressure switch fault; it will not fire.
Low System Pressure / Water Pressure Switch Open
E09
Furnace indicates a gas valve or gas supply fault; no ignition occurs despite the fan and spark.
Gas Valve Control Failure
E10
Furnace shows a fan fault; the fan does not start or runs erratically during startup.
Combustion Fan Failure
E11
Furnace displays a communication error between the user interface and the main PCB; controls are unresponsive or blank.
Control PCB Communication Fault
E12
The furnace indicates a domestic hot water sensor fault (on combi-style furnace/boiler units); hot water is unstable or unavailable.
DHW NTC Sensor Failure
E13
The furnace indicates a condensate fault and may lock out during wet or freezing conditions.
Condensate Drain Blockage / Freeze Protection Trip
E14
The furnace shows flame loss during operation; the burner repeatedly lights and goes out.
Flame Instability / Intermittent Flame Signal
E15
The furnace indicates a fan speed error; the fan runs, but its speed feedback is out of range.
Fan Speed Control / Hall Sensor Fault
E16
The furnace shows a flow switch or flow sensor fault (on systems with flow detection); the burner will not fire for heating.
Primary Flow Switch / Turbine Sensor Failure
E17
The furnace indicates an external thermostat or control signal fault and will not respond to the room thermostat.
External Control Input Error
E18
The furnace shows a power supply or polarity error and may not start or may behave erratically.
Mains Supply / Polarity Fault
E19
The furnace indicates an EEPROM or configuration error and may lock out after power-up.
PCB Configuration / Memory Fault
E20
The furnace shows an open safety chain, or the safety thermostat or limit circuit is not closed.
Safety Thermostat / Limit Circuit Open
Symptom
Domestic hot water temperature fluctuates or runs hot then cold on a combi-style Baxi furnace/boiler.
Unstable DHW Temperature Control
Symptom
Furnace emits a whistling or high-pitched noise during operation.
Gas Flow or Airflow Resonance
Symptom
Furnace fan runs continuously, even when there is no heat demand.
Fan Overrun / Stuck Relay
Symptom
Furnace frequently loses pressure and needs topping up often.
Chronic Pressure Loss
Symptom
Furnace frequently short-cycles, turning on and off every few minutes without reaching the set temperature.
Short Cycling / Poor Heat Transfer
Symptom
Furnace ignites with a loud boom or pop.
Delayed Ignition
Symptom
Furnace leaks water from the bottom of the casing or from pipe connections.
Internal Water Leak
Symptom
Furnace locks out intermittently during windy weather.
Wind-Induced Flue Disturbance
Symptom
Furnace makes loud banging or knocking noises when starting or stopping.
Kettling / Water Hammer in Primary Circuit
Symptom
Furnace produces a burning or plastic smell when running.
Overheating Components / Foreign Material on Heat Exchanger
Symptom
Furnace runs but produces no heat to the home; radiators or ducts remain cold.
No Heat Output Despite Burner Operation
Symptom
Furnace runs, but room temperature overshoots or undershoots the thermostat setting.
Poor Temperature Control / Thermostat Calibration Issue
Symptom
Furnace starts but shuts down after a few seconds without showing an error code.
Early Flame Failure / Safety Trip
Symptom
Furnace trips the household RCD or blows fuses when starting.
Electrical Short or Earth Leakage
Symptom
Furnace vibrates excessively or causes rattling in the flue or casing.
Mechanical Vibration / Imbalanced Fan
Symptom
Furnace will not start at all; no lights or display.
No Power / Dead Appliance
Symptom
Radiators heat unevenly; some remain cold even though the furnace is running normally.
Poor System Balancing / Sludge Blockage
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E01 |
Furnace fails to ignite, burner does not light, ignition sequence aborts after a few attempts.
|
Ignition Lockout | View Details |
| E02 |
Furnace locks out shortly after ignition; the burner lights briefly, then shuts down.
|
Flame Detection Failure | View Details |
| E03 |
Furnace attempts to start but shuts down with the fan running; no ignition occurs, and the flue fan may cycle.
|
Flue Fan / Air Pressure Switch Fault | View Details |
| E04 |
Furnace shuts down with an overheat indication; the flow temperature rises rapidly, then the burner cuts out.
|
Primary Heat Exchanger Overheat / High Limit Trip | View Details |
| E05 |
Furnace displays a flow temperature sensor fault; it may not start or may run erratically.
|
Flow NTC Sensor Failure | View Details |
| E06 |
Furnace shows a return temperature sensor fault; it may short-cycle or lock out.
|
Return NTC Sensor Failure | View Details |
| E07 |
Furnace indicates a flue gas sensor or flue thermostat fault; it may shut down during operation.
|
Flue Temperature Sensor / Thermostat Trip | View Details |
| E08 |
Furnace shows low water pressure or a water pressure switch fault; it will not fire.
|
Low System Pressure / Water Pressure Switch Open | View Details |
| E09 |
Furnace indicates a gas valve or gas supply fault; no ignition occurs despite the fan and spark.
|
Gas Valve Control Failure | View Details |
| E10 |
Furnace shows a fan fault; the fan does not start or runs erratically during startup.
|
Combustion Fan Failure | View Details |
| E11 |
Furnace displays a communication error between the user interface and the main PCB; controls are unresponsive or blank.
|
Control PCB Communication Fault | View Details |
| E12 |
The furnace indicates a domestic hot water sensor fault (on combi-style furnace/boiler units); hot water is unstable or unavailable.
|
DHW NTC Sensor Failure | View Details |
| E13 |
The furnace indicates a condensate fault and may lock out during wet or freezing conditions.
|
Condensate Drain Blockage / Freeze Protection Trip | View Details |
| E14 |
The furnace shows flame loss during operation; the burner repeatedly lights and goes out.
|
Flame Instability / Intermittent Flame Signal | View Details |
| E15 |
The furnace indicates a fan speed error; the fan runs, but its speed feedback is out of range.
|
Fan Speed Control / Hall Sensor Fault | View Details |
| E16 |
The furnace shows a flow switch or flow sensor fault (on systems with flow detection); the burner will not fire for heating.
|
Primary Flow Switch / Turbine Sensor Failure | View Details |
| E17 |
The furnace indicates an external thermostat or control signal fault and will not respond to the room thermostat.
|
External Control Input Error | View Details |
| E18 |
The furnace shows a power supply or polarity error and may not start or may behave erratically.
|
Mains Supply / Polarity Fault | View Details |
| E19 |
The furnace indicates an EEPROM or configuration error and may lock out after power-up.
|
PCB Configuration / Memory Fault | View Details |
| E20 |
The furnace shows an open safety chain, or the safety thermostat or limit circuit is not closed.
|
Safety Thermostat / Limit Circuit Open | View Details |
| – |
Domestic hot water temperature fluctuates or runs hot then cold on a combi-style Baxi furnace/boiler.
|
Unstable DHW Temperature Control | View Details |
| – |
Furnace emits a whistling or high-pitched noise during operation.
|
Gas Flow or Airflow Resonance | View Details |
| – |
Furnace fan runs continuously, even when there is no heat demand.
|
Fan Overrun / Stuck Relay | View Details |
| – |
Furnace frequently loses pressure and needs topping up often.
|
Chronic Pressure Loss | View Details |
| – |
Furnace frequently short-cycles, turning on and off every few minutes without reaching the set temperature.
|
Short Cycling / Poor Heat Transfer | View Details |
| – |
Furnace ignites with a loud boom or pop.
|
Delayed Ignition | View Details |
| – |
Furnace leaks water from the bottom of the casing or from pipe connections.
|
Internal Water Leak | View Details |
| – |
Furnace locks out intermittently during windy weather.
|
Wind-Induced Flue Disturbance | View Details |
| – |
Furnace makes loud banging or knocking noises when starting or stopping.
|
Kettling / Water Hammer in Primary Circuit | View Details |
| – |
Furnace produces a burning or plastic smell when running.
|
Overheating Components / Foreign Material on Heat Exchanger | View Details |
| – |
Furnace runs but produces no heat to the home; radiators or ducts remain cold.
|
No Heat Output Despite Burner Operation | View Details |
| – |
Furnace runs, but room temperature overshoots or undershoots the thermostat setting.
|
Poor Temperature Control / Thermostat Calibration Issue | View Details |
| – |
Furnace starts but shuts down after a few seconds without showing an error code.
|
Early Flame Failure / Safety Trip | View Details |
| – |
Furnace trips the household RCD or blows fuses when starting.
|
Electrical Short or Earth Leakage | View Details |
| – |
Furnace vibrates excessively or causes rattling in the flue or casing.
|
Mechanical Vibration / Imbalanced Fan | View Details |
| – |
Furnace will not start at all; no lights or display.
|
No Power / Dead Appliance | View Details |
| – |
Radiators heat unevenly; some remain cold even though the furnace is running normally.
|
Poor System Balancing / Sludge Blockage | View Details |
No matching codes found
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