BoilerFaultCodesYour boiler has shut down because the water returning to the unit is too hot, which usually means heat isn't being distributed around your home properly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Return temperature too high
What causes this fault?
This fault occurs when the water coming back into the boiler is too hot, causing the system to shut down for safety. It usually means the heat cannot escape the boiler, often due to a pump failure that isn't moving the water or a blockage in the pipework. Sometimes, a faulty sensor incorrectly reports a high temperature even when the water is cool.
This fault is frequently seen at the start of autumn when heating systems are turned on for the first time after summer, as pump components can seize up during long periods of inactivity.
DIY fix possible
Check that all radiator valves (TRVs) are fully openEnsure the boiler pressure gauge is between 1.0 and 1.5 barReset the boiler by turning the mode selector dial to 'OFF/RESET' and back to 'ON'
Find a Gas Safe engineer
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Gas Safe Register →Protect yourself from future repair bills
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