BoilerFaultCodesYour boiler has become too hot and has shut itself down as a safety precaution to prevent damage.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Overheat fault
What causes this fault?
This fault occurs when the internal temperature of the boiler exceeds safe limits, triggering a safety sensor to cut the power. It is usually caused by a lack of water flow, often due to a pump failure or a blockage in the main heat exchanger that prevents heat from being carried away from the burner.
This issue often surfaces when the heating is first turned on after summer, as pump components can seize up during long periods of inactivity.
DIY fix possible
Turn the boiler off and allow it to cool for 20 minutesCheck that your radiator valves are open and not turned to zeroPress the reset button (usually marked with a flame or 'reset' symbol) to restart the unit
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like 05 — no call-out fees, no surprises.
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