BoilerFaultCodesYour boiler has sensed that the water returning from your radiators is too hot, which usually means the heat isn't being transferred out of the system 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 traveling back into the boiler is nearly as hot as the water leaving it, usually because the heat isn't being released into your rooms. The most common reasons are a pump failure that isn't moving the water fast enough, or a blockage in the system like trapped air or sludgy radiators that prevents proper circulation.
This fault is more common in autumn when heating systems are switched back on after a long summer break, as pumps often seize during periods of inactivity.
DIY fix possible
Check that all radiator valves (TRVs) are fully open and not stuck.Ensure the central heating bypass valve, if visible, is open.Check that the internal pump is audible and running.
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