BoilerFaultCodesYour boiler has shut down because the internal water temperature is heating up much faster than it can be circulated away, usually meaning the water is stuck or the pump is struggling.
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 heat inside the boiler builds up too quickly because the heated water isn't moving through your radiators fast enough. The most common reasons are a failing circulation pump, a blockage in the system like sludge or limescale, or air trapped within the pipes.
This issue is more frequent during the first cold spell of autumn when the heating is turned back on after months of inactivity, as pumps can seize and debris can settle.
DIY fix possible
Check that your boiler pressure is between 1.0 and 1.5 bar on the digital display.Ensure at least two or three radiator valves are turned fully open to allow water flow.Try resetting the boiler by pressing the flame symbol button to see if the fault clears.
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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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