BoilerFaultCodesYour boiler has shut down because it has detected it is getting too hot, triggering a safety switch to prevent damage.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Safety thermostat (limit thermostat) activation
What causes this fault?
This fault occurs when the water inside the boiler exceeds a safe temperature, causing the safety limit thermostat to trip and shut everything down. The most common reasons are a pump failure preventing water from circulating or a buildup of limescale and sludge blocking the internal heat exchanger. It can also happen if there is trapped air in the system or if all your radiator valves are closed at once.
This fault is more common when the heating is first turned on after summer, as circulation pumps can seize up during long periods of inactivity.
DIY fix possible
Check that your radiator valves are open to allow water to flow.Ensure your system pressure is between 1.0 and 1.5 bar on the pressure gauge.Wait for the boiler to cool down and try turning the mode selector switch to 'Reset'.
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A boiler cover plan would cover faults like 02 — no call-out fees, no surprises.
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