BoilerFaultCodes.com
02 High Lockout

Your boiler has sensed that it is getting too hot and has shut itself down as a safety precaution.

Call an engineer soon

Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Overheat/Limit thermostat or burner thermostat (35e only) fault

What causes this fault?

This fault occurs when the water inside the boiler exceeds a safe temperature limit, triggering a safety sensor to cut the power. The most common reasons are a pump failure preventing heat from being moved away from the boiler, or a blockage in the pipework restricting flow. In some cases, the overheat sensor itself may have become faulty and is reporting a high temperature even if the water is cool.

Typical repair cost £90-180 (including labour)

DIY fix possible

Check that all radiator valves are fully open to allow water to flow.Wait for the boiler to cool down for at least 30 minutes.Turn the mode selector switch to the 'OFF/RESET' position and then back to 'ON'.

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