BoilerFaultCodesYour boiler has detected that a internal sensor is stuck, making the system think water is moving when it should be at rest.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Differential water flow switch fault (still closed).
What causes this fault?
This fault occurs when a mechanical sensor inside the boiler is stuck in the 'on' position, incorrectly signaling that water is flowing through the system. This is usually caused by a buildup of debris or sludge from the heating system jamming the moving parts, or a faulty pump that isn't shutting down correctly. Because the boiler thinks water is moving when it shouldn't be, it shuts down as a safety precaution to prevent damage.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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