BoilerFaultCodesYour boiler is overheating too quickly because water isn't flowing through the system correctly, often due to low pressure or trapped air.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Water shortage, temperature rise too quick: Pump blocked, low output from the pump, air in appliance, system pressure too low
What causes this fault?
This fault occurs when the boiler's internal sensors detect that the temperature is rising too rapidly, which usually means heat isn't being carried away from the heat exchanger. The most common reasons are that there isn't enough water pressure to move the heat, air bubbles are trapped in the pump, or the pump itself has seized and stopped circulating water. Basically, the boiler is producing heat faster than the system can distribute it to your radiators.
This issue often appears in autumn when the heating is turned back on for the first time after summer, as internal pump components can seize up during long periods of inactivity.
DIY fix possible
Check the pressure gauge and top up the water to 1.5 bar if it is too lowBleed any air from your radiators using a radiator keyEnsure all radiator valves and isolation valves are fully open
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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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