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 detected a critical internal fault and has locked itself out to prevent damage or unsafe operation.
Your boiler has been left in a manual testing mode after a service or inspection and needs to be switched back to its normal operating setting.
Your boiler has been left in its internal testing mode, which is usually only used by engineers during a service or setup.
Your boiler has temporarily stopped working because it has detected a blockage or restriction in the pipe that expels exhaust gases outside your home.
Your boiler has completely lost power and will not turn on at all, meaning you currently have no heating or hot water.
BoilerFaultCodes