BoilerFaultCodesYour boiler is heating up too quickly because water isn't flowing through the system properly, causing it to shut down to prevent overheating.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Water circulation fault (Temperature rise too fast)
What causes this fault?
This fault occurs when the boiler detects that the internal water temperature is rising much faster than it should, triggering a safety shutdown. The most common cause is a blockage in the system or a failing pump that prevents water from moving away from the heat exchanger quickly enough. It can also be caused by air trapped in the pipework or a buildup of debris known as central heating sludge.
This fault is specifically common in autumn when homeowners turn their heating back on for the first time, as pumps can seize up after months of inactivity during the summer.
DIY fix possible
Check that your boiler pressure is between 1.0 and 1.5 bar on the digital display.Ensure all radiator valves and isolation valves under the boiler are fully open.Bleed your radiators to remove any trapped air pockets that might be blocking flow.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like F24 — no call-out fees, no surprises.
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