BoilerFaultCodesYour boiler has shut down because a sensor has detected that the water inside is getting 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: Temperature supply sensor too high (> 101 °C).
What causes this fault?
This fault occurs because the water leaving the boiler has exceeded a safe temperature limit, causing the system to shut down for safety. It is usually caused by a lack of water flow, often due to a pump failure or a blockage within the heat exchanger that prevents heat from being carried away quickly enough. In some cases, the sensor itself may simply be faulty and providing an incorrect high-temperature reading.
This issue is more frequent during the first cold spell of autumn, when pumps that have sat idle all summer can seize up upon restarting.
DIY fix possible
Check that all radiator valves are fully open to allow water to circulateCheck that your system pressure is between 1.0 and 1.5 bar on the gaugeOnce the boiler has cooled down, try to reset the unit
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A boiler cover plan would cover faults like 4A — no call-out fees, no surprises.
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