BoilerFaultCodesYour boiler is providing hot water correctly, but it is failing to respond when you turn your heating on.
This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.
Technical description: Boiler not operating during central heating demand (HW ok)
What causes this fault?
This fault occurs when the boiler correctly recognises a request for hot water but fails to receive or act on the signal from your heating controls. The most common reason is a mechanical failure in the diverter valve, which gets stuck in the hot water position and cannot switch over to heat your radiators. It can also be caused by a faulty room thermostat or a failed motorised valve actuator that is no longer communicating with the boiler.
This issue is most frequently noticed in autumn when homeowners turn their heating back on for the first time after the summer months, often causing internal moving parts to seize from lack of use.
DIY fix possible
Check that your room thermostat is set higher than the current room temperature.Replace the batteries in your wireless wall thermostat or programmer.Ensure the heating timer or programmer is set to 'On' or 'Auto'.
Find a Gas Safe engineer
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