EHC
EHC 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 will not ignite, display shows E01 shortly after a heating or hot water demand.
Ignition Failure Lockout
E02
Boiler starts then shuts down with E02, fan runs briefly but burner does not stay lit.
Flame Detection Failure
E03
Boiler locks out with E03, fan may not start or stops quickly, no ignition attempt.
Fan or Air Pressure Switch Fault
E04
Boiler displays E04 and will not fire, often immediately on power-up.
Primary Flow Temperature Sensor Fault (NTC Open/Short)
E05
Boiler shows E05, may run briefly then shut down, often related to return temperature readings.
Return Temperature Sensor Fault
E06
Boiler locks out with E06 when hot water is demanded, heating may still work intermittently.
DHW Temperature Sensor Fault
E07
Boiler shows E07 and shuts down, often after overheating or poor circulation.
Overheat Thermostat Trip / High Limit Fault
E08
Boiler displays E08, no ignition attempt, often after a power surge or wiring issue.
Low Voltage / PCB Supply Fault
E09
Boiler shows E09 and will not run, often associated with pump or flow issues.
Water Circulation / Pump Fault
E10
Boiler displays E10, pressure gauge shows very low or zero pressure, boiler will not fire.
Low System Water Pressure
E11
Boiler shows E11, pressure gauge is high (often above 3 bar), discharge from pressure relief valve may be visible.
High System Pressure / Overpressure
E12
Boiler intermittently locks out with E12, especially during hot water use, with fluctuating temperatures.
Flow Sensor / Turbine Fault (DHW Flow Detection)
E13
Boiler shows E13, fan may run but ignition is inhibited, often related to flue or combustion safety.
Flue Gas / Combustion Safety Fault
E14
Boiler displays E14, no response to thermostat or programmer, or erratic operation.
Communication Fault (PCB to Controls)
E15
Boiler shows E15 and shuts down, often accompanied by gurgling noises or partial heating.
Air in System / Dry Fire Protection
E16
Boiler intermittently shows E16, particularly when switching between heating and hot water.
Diverter Valve Position Fault
E17
Boiler shows E17, fan runs but ignition is inhibited, often in very cold or very hot conditions.
Outside Temperature Sensor / Weather Compensation Fault
E18
Boiler displays E18, burner shuts down shortly after ignition, often with rumbling noises.
Flame Instability / Poor Combustion
E19
Boiler shows E19, no heating or hot water, often after a power cut or surge.
Internal EEPROM / Configuration Error
E20
Boiler displays E20 and shuts down, often when condensate drainage is restricted.
Condensate Drain Blockage / Sensor Fault
Symptom
Boiler cycles on and off rapidly without reaching set temperature.
Short Cycling
Symptom
Boiler display is blank but fused spur has power.
No Power to Control Panel / Dead PCB
Symptom
Boiler does not respond to room thermostat or programmer, but power light is on.
Control Signal Failure
Symptom
Boiler emits a burning smell or signs of overheating from the casing.
Electrical Overheating / Component Failure
Symptom
Boiler flue terminal shows staining or there is visible steam and smell around it.
Flue Gas Recirculation / Condensate Issues
Symptom
Boiler frequently loses pressure and needs regular topping up.
Chronic Pressure Loss
Symptom
Boiler hot water temperature fluctuates between very hot and cold during a shower.
Inconsistent DHW Temperature Control
Symptom
Boiler is very noisy with whirring or grinding sounds from inside.
Mechanical Noise from Fan or Pump
Symptom
Boiler leaking water from underneath the casing or pipe connections.
Internal Water Leak
Symptom
Boiler makes gurgling noises and sometimes fails to start after being off for a long period.
Air and Condensate Retention after Inactivity
Symptom
Boiler makes loud banging or knocking noises (kettling) during operation.
Heat Exchanger Kettling / Localised Boiling
Symptom
Boiler produces hot water but central heating does not work.
Heating Circuit Isolation / Diverter Fault
Symptom
Boiler provides central heating but no domestic hot water (on combi models).
DHW Priority / Flow Detection Issue
Symptom
Boiler runs but radiators do not get hot or only partially heat up.
Poor Heating Performance / Circulation Issue
Symptom
Boiler starts then shuts down after a few seconds without showing a specific error code.
Lockout without Displayed Code
Symptom
Boiler trips the electrical circuit breaker or RCD when it starts.
Electrical Short or Earth Leakage
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E01 |
Boiler will not ignite, display shows E01 shortly after a heating or hot water demand.
|
Ignition Failure Lockout | View Details |
| E02 |
Boiler starts then shuts down with E02, fan runs briefly but burner does not stay lit.
|
Flame Detection Failure | View Details |
| E03 |
Boiler locks out with E03, fan may not start or stops quickly, no ignition attempt.
|
Fan or Air Pressure Switch Fault | View Details |
| E04 |
Boiler displays E04 and will not fire, often immediately on power-up.
|
Primary Flow Temperature Sensor Fault (NTC Open/Short) | View Details |
| E05 |
Boiler shows E05, may run briefly then shut down, often related to return temperature readings.
|
Return Temperature Sensor Fault | View Details |
| E06 |
Boiler locks out with E06 when hot water is demanded, heating may still work intermittently.
|
DHW Temperature Sensor Fault | View Details |
| E07 |
Boiler shows E07 and shuts down, often after overheating or poor circulation.
|
Overheat Thermostat Trip / High Limit Fault | View Details |
| E08 |
Boiler displays E08, no ignition attempt, often after a power surge or wiring issue.
|
Low Voltage / PCB Supply Fault | View Details |
| E09 |
Boiler shows E09 and will not run, often associated with pump or flow issues.
|
Water Circulation / Pump Fault | View Details |
| E10 |
Boiler displays E10, pressure gauge shows very low or zero pressure, boiler will not fire.
|
Low System Water Pressure | View Details |
| E11 |
Boiler shows E11, pressure gauge is high (often above 3 bar), discharge from pressure relief valve may be visible.
|
High System Pressure / Overpressure | View Details |
| E12 |
Boiler intermittently locks out with E12, especially during hot water use, with fluctuating temperatures.
|
Flow Sensor / Turbine Fault (DHW Flow Detection) | View Details |
| E13 |
Boiler shows E13, fan may run but ignition is inhibited, often related to flue or combustion safety.
|
Flue Gas / Combustion Safety Fault | View Details |
| E14 |
Boiler displays E14, no response to thermostat or programmer, or erratic operation.
|
Communication Fault (PCB to Controls) | View Details |
| E15 |
Boiler shows E15 and shuts down, often accompanied by gurgling noises or partial heating.
|
Air in System / Dry Fire Protection | View Details |
| E16 |
Boiler intermittently shows E16, particularly when switching between heating and hot water.
|
Diverter Valve Position Fault | View Details |
| E17 |
Boiler shows E17, fan runs but ignition is inhibited, often in very cold or very hot conditions.
|
Outside Temperature Sensor / Weather Compensation Fault | View Details |
| E18 |
Boiler displays E18, burner shuts down shortly after ignition, often with rumbling noises.
|
Flame Instability / Poor Combustion | View Details |
| E19 |
Boiler shows E19, no heating or hot water, often after a power cut or surge.
|
Internal EEPROM / Configuration Error | View Details |
| E20 |
Boiler displays E20 and shuts down, often when condensate drainage is restricted.
|
Condensate Drain Blockage / Sensor Fault | View Details |
| – |
Boiler cycles on and off rapidly without reaching set temperature.
|
Short Cycling | View Details |
| – |
Boiler display is blank but fused spur has power.
|
No Power to Control Panel / Dead PCB | View Details |
| – |
Boiler does not respond to room thermostat or programmer, but power light is on.
|
Control Signal Failure | View Details |
| – |
Boiler emits a burning smell or signs of overheating from the casing.
|
Electrical Overheating / Component Failure | View Details |
| – |
Boiler flue terminal shows staining or there is visible steam and smell around it.
|
Flue Gas Recirculation / Condensate Issues | View Details |
| – |
Boiler frequently loses pressure and needs regular topping up.
|
Chronic Pressure Loss | View Details |
| – |
Boiler hot water temperature fluctuates between very hot and cold during a shower.
|
Inconsistent DHW Temperature Control | View Details |
| – |
Boiler is very noisy with whirring or grinding sounds from inside.
|
Mechanical Noise from Fan or Pump | View Details |
| – |
Boiler leaking water from underneath the casing or pipe connections.
|
Internal Water Leak | View Details |
| – |
Boiler makes gurgling noises and sometimes fails to start after being off for a long period.
|
Air and Condensate Retention after Inactivity | View Details |
| – |
Boiler makes loud banging or knocking noises (kettling) during operation.
|
Heat Exchanger Kettling / Localised Boiling | View Details |
| – |
Boiler produces hot water but central heating does not work.
|
Heating Circuit Isolation / Diverter Fault | View Details |
| – |
Boiler provides central heating but no domestic hot water (on combi models).
|
DHW Priority / Flow Detection Issue | View Details |
| – |
Boiler runs but radiators do not get hot or only partially heat up.
|
Poor Heating Performance / Circulation Issue | View Details |
| – |
Boiler starts then shuts down after a few seconds without showing a specific error code.
|
Lockout without Displayed Code | View Details |
| – |
Boiler trips the electrical circuit breaker or RCD when it starts.
|
Electrical Short or Earth Leakage | View Details |
No matching codes found
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