BoilerFaultCodesYour boiler has detected that water is still circulating or a sensor is stuck even when the pump should be off.
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 is still closed
What causes this fault?
This fault occurs when the boiler's internal sensors believe water is still moving through the system even after the pump has been told to stop. This is usually caused by a mechanical sensor becoming stuck in the 'on' position due to debris in the system water, or a pump that is failing to switch off correctly. It acts as a safety measure to prevent the boiler from firing when it cannot accurately control the flow of water.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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