BoilerFaultCodesYour boiler has switched itself off for safety because the internal water temperature has become too hot.
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 THERMOSTAT: The appliance will enter a lockout condition in the event of overheating.
What causes this fault?
This fault occurs when the water inside the boiler exceeds a safe temperature, triggering a safety switch to kill the flame. The most common reasons are a failed pump that isn't moving water away from the heat exchanger quickly enough, or a buildup of sludge and debris creating a blockage in the system.
This fault is frequently seen at the start of autumn when heating systems are switched back on after being idle, as circulation pumps can seize during the summer months.
DIY fix possible
Check that your radiator valves are turned on and not closed.Wait for the boiler to cool down for at least 30 minutes.Press and hold the reset button for 5 seconds to clear the fault.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
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