Baxi Water Heaters Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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E01
Water heater does not ignite, the burner does not light, and the display shows E01 shortly after a hot water demand.
Ignition Failure Lockout
E02
Water heater locks out with E02; the burner shuts down shortly after ignition or during operation.
Flame Loss / Flame Detection Fault
E03
The unit attempts to start but quickly shuts down with E03; the fan may run briefly, but there is no sustained flame.
Flue / Air Pressure Switch Fault
E04
The display shows E04, and the heater will not start; this may occur immediately on power-up.
Overheat Thermostat Trip / Safety Thermostat Open
E05
The heater locks out with E05, often after running for a short period; this may be accompanied by high temperature readings.
Flow Temperature Sensor Fault
E06
The display shows E06; water temperature fluctuates, or the unit shuts down unexpectedly.
Return Temperature Sensor Fault
E07
Heater displays E07 and will not operate; may be associated with very low or no water flow.
Water Flow Sensor / Turbine Fault
E08
Unit displays E08 and stops; this may occur when hot water demand is high or during long draws.
Outlet Temperature Sensor Fault / DHW NTC Error
E09
Heater locks out with E09, often accompanied by unusual noises from the combustion area.
Gas Valve / Modulation Fault
E10
Display shows E10, unit may not start or may shut down intermittently.
Fan / Combustion Air Fault
E11
Heater displays E11 and will not operate; this may be associated with low system pressure on models with sealed primary circuits.
Low Water Pressure / Pressure Switch Fault
E12
Display shows E12, unit may behave erratically or not respond to controls.
Control PCB Communication / Internal Fault
E13
Heater displays E13, often associated with condensate issues on condensing models.
Condensate Drain / Siphon Fault
E14
Display shows E14, unit may not respond to user inputs or may show incorrect temperatures.
User Interface / Display Board Fault
E15
Heater displays E15 and shuts down, often during high temperature operation.
Flue Gas Overtemperature / Flue Sensor Fault
E16
Intermittent E16 error, unit may cycle on and off rapidly or fail to modulate correctly.
Modulation / Output Control Fault
E17
Heater displays E17, often associated with sensor readings outside the expected range.
Sensor Range / Calibration Error
E18
E18 appears, and the heater may not start or may shut down during operation.
Power Supply / Voltage Fault
E19
The heater shows E19, which may be associated with communication between different internal modules.
Internal Communication Fault
E20
E20 error: The heater may not start or may shut down with no obvious mechanical issue.
General Lockout / Undefined Fault
Symptom
Burning or electrical smell from the Baxi water heater casing during or after operation.
Overheating Electrical Component
Symptom
Hot water temperature is fine initially but gradually drops to cold during a long shower, then recovers after a pause.
Thermal Cutback / Overheat Protection Cycling
Symptom
Loud whistling or roaring noise from the burner area when the Baxi water heater is firing.
Combustion Noise / Burner Instability
Symptom
No hot water at any tap; the Baxi water heater appears powered, but the burner does not ignite when a hot tap is opened.
No Demand Recognition / Flow Detection Failure
Symptom
Persistent smell of gas near the Baxi water heater, even when it is not firing.
Gas Leak
Symptom
Soot or black staining around the flue terminal or on the casing of the Baxi water heater.
Incomplete Combustion / Sooting
Symptom
The Baxi water heater frequently needs manual resetting to restore operation, even though hot water is available between resets.
Intermittent Lockout Due to Marginal Conditions
Symptom
The Baxi water heater is completely dead; there are no lights or display, and no response to controls.
No Power / Electrical Supply Failure
Symptom
The Baxi water heater runs but delivers water that is too hot, even at low temperature settings.
Overheating / Temperature Control Failure
Symptom
The Baxi water heater trips the household RCD or circuit breaker when it attempts to start.
Electrical Short or Earth Leakage
Symptom
The heater starts normally but shuts down as soon as another large water appliance (e.g., washing machine) is used.
Supply Interaction / Flow or Pressure Drop
Symptom
The heater vibrates excessively or rattles when the fan or burner is running.
Mechanical Vibration / Mounting Fault
Symptom
The water heater ignites, but the water is only lukewarm even at the maximum temperature setting.
Insufficient Heating Output
Symptom
The water heater produces hot water, but the temperature is unstable, alternating between very hot and cold during a shower.
Temperature Modulation / Flow Control Instability
Symptom
The water heater repeatedly starts and stops (short cycling) during hot water use, causing fluctuating temperatures.
Short Cycling Due to Flow or Sensor Issues
Symptom
Unusual banging or knocking noises from the Baxi water heater during operation (kettling).
Heat Exchanger Kettling Due to Limescale
Symptom
Visible water leak from the bottom of the Baxi water heater casing.
Internal Water Leak
Symptom
Water leaking from the flue area or from a plastic drain near the base of a condensing Baxi water heater.
Condensate Leak
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E01 |
Water heater does not ignite, the burner does not light, and the display shows E01 shortly after a hot water demand.
|
Ignition Failure Lockout | View Details |
| E02 |
Water heater locks out with E02; the burner shuts down shortly after ignition or during operation.
|
Flame Loss / Flame Detection Fault | View Details |
| E03 |
The unit attempts to start but quickly shuts down with E03; the fan may run briefly, but there is no sustained flame.
|
Flue / Air Pressure Switch Fault | View Details |
| E04 |
The display shows E04, and the heater will not start; this may occur immediately on power-up.
|
Overheat Thermostat Trip / Safety Thermostat Open | View Details |
| E05 |
The heater locks out with E05, often after running for a short period; this may be accompanied by high temperature readings.
|
Flow Temperature Sensor Fault | View Details |
| E06 |
The display shows E06; water temperature fluctuates, or the unit shuts down unexpectedly.
|
Return Temperature Sensor Fault | View Details |
| E07 |
Heater displays E07 and will not operate; may be associated with very low or no water flow.
|
Water Flow Sensor / Turbine Fault | View Details |
| E08 |
Unit displays E08 and stops; this may occur when hot water demand is high or during long draws.
|
Outlet Temperature Sensor Fault / DHW NTC Error | View Details |
| E09 |
Heater locks out with E09, often accompanied by unusual noises from the combustion area.
|
Gas Valve / Modulation Fault | View Details |
| E10 |
Display shows E10, unit may not start or may shut down intermittently.
|
Fan / Combustion Air Fault | View Details |
| E11 |
Heater displays E11 and will not operate; this may be associated with low system pressure on models with sealed primary circuits.
|
Low Water Pressure / Pressure Switch Fault | View Details |
| E12 |
Display shows E12, unit may behave erratically or not respond to controls.
|
Control PCB Communication / Internal Fault | View Details |
| E13 |
Heater displays E13, often associated with condensate issues on condensing models.
|
Condensate Drain / Siphon Fault | View Details |
| E14 |
Display shows E14, unit may not respond to user inputs or may show incorrect temperatures.
|
User Interface / Display Board Fault | View Details |
| E15 |
Heater displays E15 and shuts down, often during high temperature operation.
|
Flue Gas Overtemperature / Flue Sensor Fault | View Details |
| E16 |
Intermittent E16 error, unit may cycle on and off rapidly or fail to modulate correctly.
|
Modulation / Output Control Fault | View Details |
| E17 |
Heater displays E17, often associated with sensor readings outside the expected range.
|
Sensor Range / Calibration Error | View Details |
| E18 |
E18 appears, and the heater may not start or may shut down during operation.
|
Power Supply / Voltage Fault | View Details |
| E19 |
The heater shows E19, which may be associated with communication between different internal modules.
|
Internal Communication Fault | View Details |
| E20 |
E20 error: The heater may not start or may shut down with no obvious mechanical issue.
|
General Lockout / Undefined Fault | View Details |
| – |
Burning or electrical smell from the Baxi water heater casing during or after operation.
|
Overheating Electrical Component | View Details |
| – |
Hot water temperature is fine initially but gradually drops to cold during a long shower, then recovers after a pause.
|
Thermal Cutback / Overheat Protection Cycling | View Details |
| – |
Loud whistling or roaring noise from the burner area when the Baxi water heater is firing.
|
Combustion Noise / Burner Instability | View Details |
| – |
No hot water at any tap; the Baxi water heater appears powered, but the burner does not ignite when a hot tap is opened.
|
No Demand Recognition / Flow Detection Failure | View Details |
| – |
Persistent smell of gas near the Baxi water heater, even when it is not firing.
|
Gas Leak | View Details |
| – |
Soot or black staining around the flue terminal or on the casing of the Baxi water heater.
|
Incomplete Combustion / Sooting | View Details |
| – |
The Baxi water heater frequently needs manual resetting to restore operation, even though hot water is available between resets.
|
Intermittent Lockout Due to Marginal Conditions | View Details |
| – |
The Baxi water heater is completely dead; there are no lights or display, and no response to controls.
|
No Power / Electrical Supply Failure | View Details |
| – |
The Baxi water heater runs but delivers water that is too hot, even at low temperature settings.
|
Overheating / Temperature Control Failure | View Details |
| – |
The Baxi water heater trips the household RCD or circuit breaker when it attempts to start.
|
Electrical Short or Earth Leakage | View Details |
| – |
The heater starts normally but shuts down as soon as another large water appliance (e.g., washing machine) is used.
|
Supply Interaction / Flow or Pressure Drop | View Details |
| – |
The heater vibrates excessively or rattles when the fan or burner is running.
|
Mechanical Vibration / Mounting Fault | View Details |
| – |
The water heater ignites, but the water is only lukewarm even at the maximum temperature setting.
|
Insufficient Heating Output | View Details |
| – |
The water heater produces hot water, but the temperature is unstable, alternating between very hot and cold during a shower.
|
Temperature Modulation / Flow Control Instability | View Details |
| – |
The water heater repeatedly starts and stops (short cycling) during hot water use, causing fluctuating temperatures.
|
Short Cycling Due to Flow or Sensor Issues | View Details |
| – |
Unusual banging or knocking noises from the Baxi water heater during operation (kettling).
|
Heat Exchanger Kettling Due to Limescale | View Details |
| – |
Visible water leak from the bottom of the Baxi water heater casing.
|
Internal Water Leak | View Details |
| – |
Water leaking from the flue area or from a plastic drain near the base of a condensing Baxi water heater.
|
Condensate Leak | View Details |
No matching codes found
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