BoilerFaultCodesWhat the manual says
Manufacturer manual3-Way Valve does not Operate and No DHW
What causes this fault?
This fault occurs when the mechanical part responsible for directing hot water to either your taps or your radiators becomes stuck or suffers an electrical failure. The most common reason is that the moving parts inside the valve have become seized by debris in the system water, or the small motor that pushes the valve has burnt out. Because the boiler cannot safely confirm where the heat is going, it stops operating to prevent overheating.
This issue is more frequent in autumn when the heating is turned on for the first time after summer, as the valve can seize up due to months of inactivity.
Engineer required
This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Avoid the next call-out bill
A cover plan would handle faults like 9.1.35: no call-out fees, no surprise bills.
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