14 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Concord CXD
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Your boiler has detected an internal fault that prevents it from operating safely or correctly.
Your boiler is failing to detect that it has enough airflow to safely light the flame, so it has shut itself down to prevent a potentially hazardous situation.
Your boiler has detected an issue with its internal sensors and has stopped running to prevent any damage or incorrect temperature readings.
Your boiler has lost its ability to accurately measure the temperature of the water being heated for your radiators, causing it to stop running as a safety precaution.
Your boiler is failing to start because it cannot successfully ignite the gas after several attempts.
Your boiler has stopped working because it cannot light the internal flame safely, so it has locked itself to prevent gas from flowing.
Your boiler has stopped working because the internal component responsible for pushing stale air and gases out of the flue is not functioning correctly.
Your boiler has detected that a internal safety sensor is not reading correctly, which prevents it from safely heating your home.
Your boiler is unable to safely control the flow of gas needed to stay lit, so it has shut down to avoid a potential hazard.
Your boiler has stopped working because it failed to ignite the gas burner after five repeated attempts.
Your boiler is struggling because it has lost the signal from the temperature sensor installed on the outside of your property, which tells it how hard to work based on the weather.
Your boiler has shut itself down as a safety precaution because the water inside has become far too hot.
Your boiler has detected that water is failing to circulate correctly through the system, which will prevent it from heating your home or providing hot water.
Your boiler is unable to move hot water around the system, meaning your heating and hot water will not work.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes