BoilerFaultCodesYour boiler has shut down because its internal temperature has risen too high, usually due to a lack of water flow or a circulation blockage.
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 water inside the boiler exceeds a safe temperature, triggering a safety shutdown to prevent damage. The most common reason is a failure of the internal pump to move water through the heat exchanger, or a blockage caused by a build-up of debris and sludge within the system.
This fault is more common when the heating is first turned on after summer, as the internal pump can seize up during long periods of inactivity.
DIY fix possible
Check that your boiler pressure is between 1.0 and 1.5 bar on the gauge; top up if low.Ensure all radiator valves and isolation valves under the boiler are fully open.Wait 30 minutes for the unit to cool down, then press the reset button (usually marked with a flame or 'reset').
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A boiler cover plan would cover faults like F5 — 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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