Attack
Attack Boilers Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
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E01
Boiler does not ignite, display shows E01 shortly after a heating or DHW demand.
Ignition Failure / No Flame Detected
E02
Boiler locks out with E02, burner stops shortly after ignition or during operation.
Flame Loss During Operation
E03
Boiler shows E03 and does not start the burner; fan may run briefly then stop.
Flue Gas / Air Pressure Switch Fault
E04
Boiler displays E04 and shuts down; may occur after overheating or poor circulation.
Overheat Thermostat Trip / Safety Temperature Limiter
E05
Boiler shows E05, heating or DHW does not start; temperature reading may be abnormal.
Flow Temperature Sensor Fault (NTC Open/Short)
E06
Boiler displays E06, domestic hot water (DHW) may not function correctly or temperature is erratic.
DHW Temperature Sensor Fault (NTC Open/Short)
E07
Boiler shows E07 and will not operate; may be associated with very low or very high system pressure.
Water Pressure Sensor / Switch Fault
E08
Boiler locks out with E08; fan may not start or runs erratically.
Fan Motor / Fan Speed Control Fault
E09
Boiler shows E09 and stops; may be associated with very high flow temperature.
Primary Flow Overtemperature / High Limit
E10
Boiler displays E10 and will not start; often associated with low water pressure or empty system.
Low Water Pressure Lockout
E11
Boiler shows E11; may be related to return temperature sensor reading out of range.
Return Temperature Sensor Fault (NTC Open/Short)
E12
Boiler displays E12 and stops; may be associated with flue gas sensor or safety device.
Flue Gas Temperature Sensor / Safety Device Fault
E13
Boiler shows E13; may be related to condensate system malfunction.
Condensate Drain / Level Fault
E14
Boiler displays E14; ignition may not start or may be erratic.
Gas Valve Control / Modulation Fault
E15
Boiler shows E15; may be associated with internal leak detection or low insulation resistance.
Water Leak / Internal Safety Sensor Fault
E16
Boiler displays E16; control panel may be unresponsive or show abnormal readings.
Main Control PCB Fault
E17
Boiler shows E17; may be related to incorrect parameter settings or communication error.
Configuration / Parameter Error
E18
Boiler displays E18; may be associated with external sensor or weather compensation probe.
Outdoor Temperature Sensor Fault
E19
Boiler shows E19; may be related to domestic hot water flow detection.
DHW Flow Sensor / Turbine Fault
E20
Boiler displays E20; may be associated with pump or flow switch malfunction.
Circulation Pump / Flow Fault
Symptom
Boiler cycles on and off rapidly, with short burner run times and unstable temperatures.
Short Cycling / Control Instability
Symptom
Boiler display is completely blank and unresponsive.
No Power / Control Panel Failure
Symptom
Boiler display is on but shows incorrect or fluctuating temperatures.
Sensor Calibration / Wiring Issue
Symptom
Boiler does not respond to room thermostat; heating does not start even though boiler is powered.
External Control / Thermostat Fault
Symptom
Boiler emits a burning or electrical smell during operation.
Overheating Electrical Component
Symptom
Boiler emits a strong smell of gas near the appliance, even when not running.
Gas Leak at Boiler
Symptom
Boiler fan runs continuously even when there is no demand for heating or hot water.
Stuck Fan Relay / Post‑Purge Control Fault
Symptom
Boiler flue terminal drips large amounts of water or stains the wall.
Condensate / Flue Drainage Issue
Symptom
Boiler frequently locks out and requires manual reset, with varying error codes or sometimes none.
Intermittent Electrical / Control Fault
Symptom
Boiler frequently loses pressure and needs topping up every few days.
Chronic Pressure Loss
Symptom
Boiler is very noisy during operation, with whistling or roaring from the burner area.
Combustion Noise / Incorrect Gas-Air Ratio
Symptom
Boiler leaking water from underneath the casing or from pipe connections.
Internal Water Leak
Symptom
Boiler makes loud banging or knocking noises when starting or stopping.
Kettling / Hydraulic Shock
Symptom
Boiler runs but radiators remain cold or only lukewarm.
Poor Heating Circulation
Symptom
Boiler starts then shuts down after a few seconds without showing a specific error code.
Flame Detection / Early Shutdown
Symptom
Radiators get hot but domestic hot water from taps is cold or only lukewarm on a combi boiler.
DHW Production Failure
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E01 |
Boiler does not ignite, display shows E01 shortly after a heating or DHW demand.
|
Ignition Failure / No Flame Detected | View Details |
| E02 |
Boiler locks out with E02, burner stops shortly after ignition or during operation.
|
Flame Loss During Operation | View Details |
| E03 |
Boiler shows E03 and does not start the burner; fan may run briefly then stop.
|
Flue Gas / Air Pressure Switch Fault | View Details |
| E04 |
Boiler displays E04 and shuts down; may occur after overheating or poor circulation.
|
Overheat Thermostat Trip / Safety Temperature Limiter | View Details |
| E05 |
Boiler shows E05, heating or DHW does not start; temperature reading may be abnormal.
|
Flow Temperature Sensor Fault (NTC Open/Short) | View Details |
| E06 |
Boiler displays E06, domestic hot water (DHW) may not function correctly or temperature is erratic.
|
DHW Temperature Sensor Fault (NTC Open/Short) | View Details |
| E07 |
Boiler shows E07 and will not operate; may be associated with very low or very high system pressure.
|
Water Pressure Sensor / Switch Fault | View Details |
| E08 |
Boiler locks out with E08; fan may not start or runs erratically.
|
Fan Motor / Fan Speed Control Fault | View Details |
| E09 |
Boiler shows E09 and stops; may be associated with very high flow temperature.
|
Primary Flow Overtemperature / High Limit | View Details |
| E10 |
Boiler displays E10 and will not start; often associated with low water pressure or empty system.
|
Low Water Pressure Lockout | View Details |
| E11 |
Boiler shows E11; may be related to return temperature sensor reading out of range.
|
Return Temperature Sensor Fault (NTC Open/Short) | View Details |
| E12 |
Boiler displays E12 and stops; may be associated with flue gas sensor or safety device.
|
Flue Gas Temperature Sensor / Safety Device Fault | View Details |
| E13 |
Boiler shows E13; may be related to condensate system malfunction.
|
Condensate Drain / Level Fault | View Details |
| E14 |
Boiler displays E14; ignition may not start or may be erratic.
|
Gas Valve Control / Modulation Fault | View Details |
| E15 |
Boiler shows E15; may be associated with internal leak detection or low insulation resistance.
|
Water Leak / Internal Safety Sensor Fault | View Details |
| E16 |
Boiler displays E16; control panel may be unresponsive or show abnormal readings.
|
Main Control PCB Fault | View Details |
| E17 |
Boiler shows E17; may be related to incorrect parameter settings or communication error.
|
Configuration / Parameter Error | View Details |
| E18 |
Boiler displays E18; may be associated with external sensor or weather compensation probe.
|
Outdoor Temperature Sensor Fault | View Details |
| E19 |
Boiler shows E19; may be related to domestic hot water flow detection.
|
DHW Flow Sensor / Turbine Fault | View Details |
| E20 |
Boiler displays E20; may be associated with pump or flow switch malfunction.
|
Circulation Pump / Flow Fault | View Details |
| – |
Boiler cycles on and off rapidly, with short burner run times and unstable temperatures.
|
Short Cycling / Control Instability | View Details |
| – |
Boiler display is completely blank and unresponsive.
|
No Power / Control Panel Failure | View Details |
| – |
Boiler display is on but shows incorrect or fluctuating temperatures.
|
Sensor Calibration / Wiring Issue | View Details |
| – |
Boiler does not respond to room thermostat; heating does not start even though boiler is powered.
|
External Control / Thermostat Fault | View Details |
| – |
Boiler emits a burning or electrical smell during operation.
|
Overheating Electrical Component | View Details |
| – |
Boiler emits a strong smell of gas near the appliance, even when not running.
|
Gas Leak at Boiler | View Details |
| – |
Boiler fan runs continuously even when there is no demand for heating or hot water.
|
Stuck Fan Relay / Post‑Purge Control Fault | View Details |
| – |
Boiler flue terminal drips large amounts of water or stains the wall.
|
Condensate / Flue Drainage Issue | View Details |
| – |
Boiler frequently locks out and requires manual reset, with varying error codes or sometimes none.
|
Intermittent Electrical / Control Fault | View Details |
| – |
Boiler frequently loses pressure and needs topping up every few days.
|
Chronic Pressure Loss | View Details |
| – |
Boiler is very noisy during operation, with whistling or roaring from the burner area.
|
Combustion Noise / Incorrect Gas-Air Ratio | View Details |
| – |
Boiler leaking water from underneath the casing or from pipe connections.
|
Internal Water Leak | View Details |
| – |
Boiler makes loud banging or knocking noises when starting or stopping.
|
Kettling / Hydraulic Shock | View Details |
| – |
Boiler runs but radiators remain cold or only lukewarm.
|
Poor Heating Circulation | View Details |
| – |
Boiler starts then shuts down after a few seconds without showing a specific error code.
|
Flame Detection / Early Shutdown | View Details |
| – |
Radiators get hot but domestic hot water from taps is cold or only lukewarm on a combi boiler.
|
DHW Production Failure | View Details |
No matching codes found
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