BoilerFaultCodesYour boiler has stopped working because the internal pump that moves water around your system has become stuck or blocked.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Pump blockage
What causes this fault?
This fault occurs when the main pump is unable to rotate, preventing hot water from leaving the boiler. The most common reason is a buildup of black iron oxide sludge that has jammed the internal components, or the pump has simply reached the end of its mechanical life. When the sensor detects that the water isn't moving as it should, the boiler shuts down to prevent overheating.
This fault is frequently seen in autumn when the heating is turned back on for the first time, as debris often settles and seizes the pump during the summer months.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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