5 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
This boiler uses LED flash patterns
Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →
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Your boiler has stopped working because it cannot safely clear away waste gases, likely due to a mechanical issue with internal air circulation.
Your boiler has detected a problem with the temperature sensor that controls your central heating, meaning it cannot accurately measure how hot the water is.
Your boiler has detected that water isn't moving through the system properly, causing it to overheat and shut down for safety.
Your boiler has shut down because it has detected an internal temperature that is too high or a problem with how exhaust gases are leaving the flue.
Your boiler has stopped working because it cannot light the gas flame or it cannot detect that the flame has started.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes