BoilerFaultCodesYour boiler has sensed it is getting too hot and has shut itself down as a safety precaution.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Overheat condition occurs
What causes this fault?
This fault happens when water inside the boiler reaches a temperature that is no longer safe, triggering an automatic shutdown to prevent damage. It is usually caused by a pump failure preventing water from moving away from the heat exchanger, or a build-up of sludge and debris that blocks the flow. In some cases, a faulty sensor might also incorrectly signal that the system is overheating.
This issue often surfaces in autumn when the heating is turned on for the first time after summer, as internal pump parts can seize during long periods of inactivity.
DIY fix possible
Check that all radiator valves are fully open to allow water to flow.Ensure the system pressure is between 1 and 1.5 bar on the pressure gauge.Turn the control knob to the 'Reset' position for five seconds and then back to 'On'.
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A boiler cover plan would cover faults like Lockout (Red) flashing — no call-out fees, no surprises.
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Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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