BoilerFaultCodesYour boiler has shut down because it has detected it is getting too hot, or there is a loose internal connection.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Overheat device operated or faulty, or continuity break in yellow link
What causes this fault?
This fault occurs when the boiler's internal temperature exceeds a safe limit, causing a safety sensor to cut the power. The most common reasons are a failed pump stopping water from circulating or a build-up of sludge and debris creating a blockage in the heat exchanger. In some cases, it can also be triggered by a simple loose wire or a faulty sensor providing an incorrect reading.
This issue often surfaces when the heating is first turned on after summer, as the pump can seize up from months of inactivity.
DIY fix possible
Check that your radiator valves are open and not turned to zeroEnsure your system pressure is at the correct level (usually 1.0 to 1.5 bar on the gauge)Switch the boiler off and back on again to attempt a reset once the unit has cooled down
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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