BoilerFaultCodesYour boiler has switched itself off because it has become too hot internally, likely due to a circulation problem or a faulty safety sensor.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Overheat cut off device tripped. Thermostat, Overheat cut off device, Water differential pressure switch, or faulty Pump.
What causes this fault?
This fault occurs when the water inside the boiler exceeds a safe temperature, triggering a safety switch to shut the system down to prevent damage. The most common reasons are a pump failure preventing heat from leaving the boiler or a blockage in the system restricting water flow. It can also be caused by a faulty internal sensor that is incorrectly detecting a high temperature.
This issue often surfaces when the heating is first turned on after summer, as the internal pump can seize or get stuck during long periods of inactivity.
DIY fix possible
Check that your pump is running and not stuckEnsure all radiator valves are open to allow water flowOnce the unit has cooled, press the reset button located on the overheat thermostat (refer to manual for exact location)
Find a Gas Safe engineer
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A boiler cover plan would cover faults like Neon2 — no call-out fees, no surprises.
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