12 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: Baxi 400 Heat
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's fan is failing to start or run correctly, which means the system cannot safely clear waste gases and will not fire up for your heating.
Your boiler is not receiving enough electrical power from the main supply to operate safely.
Your boiler has shut down because it has become too hot and needs to be safely reset after cooling down.
Your boiler's electronic control board has developed a fault, meaning the internal computer can no longer safely operate the heating system.
Your boiler's internal computer has developed an electrical fault and is unable to control the heating process.
Your boiler has detected that water is not moving through the system properly or there isn't enough water inside the unit to safely heat up.
Your boiler has detected a problem with its internal temperature sensor and has stopped working as a safety precaution.
Your boiler has detected that the electrical wiring coming into the unit is connected the wrong way around, causing it to shut down for safety.
Your boiler's internal computer has developed a fault and can no longer control the heating process safely.
Your boiler is not receiving any electricity and has completely powered down.
Your boiler has tried to start up several times but failed to light the flame, causing it to shut down for safety.
Your boiler has detected an internal electrical communication problem between its main control components.
BoilerFaultCodes