BoilerFaultCodesYour boiler has shut down because it is heating up much faster than it should, usually because the water isn't moving through the system properly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Safety switch-off: Temperature rise too fast
What causes this fault?
This fault occurs when the boiler sensors detect that the internal water temperature is rising at an unnaturally high rate, causing the system to shut down for safety. The most common reason is a blockage or a pump failure that prevents water from flowing through the boiler to your radiators. It can also be caused by air trapped in the system or a build-up of sludge that is restricting the heat exchanger.
This issue often appears when the heating is turned back on for the first time in autumn, as the internal pump can seize up after sitting idle throughout the summer.
DIY fix possible
Check that your radiator valves are openEnsure the boiler pressure is between 1.0 and 1.5 barTry resetting the boiler to see if the fault clears
Find a Gas Safe engineer
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Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like F.24 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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