BoilerFaultCodesYour boiler has detected an issue with the external valve system, preventing it from operating correctly and resulting in a total loss of heating and hot water.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: External valve
What causes this fault?
This fault occurs when the boiler is unable to communicate with or operate the external valves that direct water to your radiators or hot water cylinder. The most common cause is a mechanical failure in the motorised valve head or a loose connection within the wiring center that manages your heating controls.
This fault is more frequent in autumn when heating systems are switched back on after a long summer break, often causing internal valve components to seize.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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