BoilerFaultCodesYour boiler has switched itself off because it has become too hot internally, preventing any damage to the unit.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Boiler overheat thermostat will shut down the boiler in the event of overheating
What causes this fault?
This fault occurs when water inside the boiler reaches an unsafe temperature, triggering a safety switch to shut the system down. It is often caused by a lack of water flow, which can happen if the internal pump has failed or if there is a significant blockage trapped within the main heat exchanger.
This issue often surfaces during autumn when the heating is turned back on after a long summer break, as internal pump parts may have seized during the period of inactivity.
DIY fix possible
Check that all radiator valves (TRVs) are fully open to allow water to flow.Ensure there is enough water pressure in the system by checking the pressure gauge.Wait for the boiler to cool down and then press the reset button or turn the control knob to 'Reset'.
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A boiler cover plan would cover faults like Fault led (B) illuminated (Overheat) — no call-out fees, no surprises.
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Ideal Boxer C is discontinued — time for a new one?
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