BoilerFaultCodesYour boiler has reached an unsafe temperature and has shut itself down to prevent damage or overheating.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Over temperature on primary water circuit
What causes this fault?
This fault occurs when the water inside the boiler gets too hot, causing a safety sensor to trip and shut the system down. The most common reasons are a pump that has stopped moving water around the system or a build-up of sludge and debris that is blocking the internal pipework.
This fault is more common when the heating is first turned back on in autumn, as static water can lead to pump seizures or settled debris causing blockages.
DIY fix possible
Check that all radiator valves are fully open to allow water to circulate.Ensure the boiler pressure gauge is between 1.0 and 1.5 bar.Reset the boiler using the power button or reset switch and see if the fault clears.
Find a Gas Safe engineer
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