BoilerFaultCodesYour boiler has shut down because its internal safety sensor has detected that the water temperature has risen too high.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Limit thermostat fault
What causes this fault?
This fault occurs when the water inside the heat exchanger reaches a dangerously high temperature, triggering a safety switch to prevent damage. The most common reasons are a pump failure that stops water from moving or a blockage in the system that prevents heat from escaping the boiler. It can also be caused by a faulty sensor sending an incorrect 'overheat' signal to the main control board.
This issue is more frequent when the heating is first turned on after summer, as pump components often seize up during long periods of inactivity.
DIY fix possible
Check that all radiator valves and boiler isolation valves are fully openTurn the selector switch to the 'OFF/RESET' position, wait five seconds, and turn it back to 'ON'Check that your system pressure is between 1 and 1.5 bar on the pressure gauge
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
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