BoilerFaultCodesYour boiler's internal pump has stopped spinning, which means hot water cannot be moved around the system to heat your home or taps.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Pump Rotor Blocked: Clear blockage
What causes this fault?
This fault occurs when debris, such as iron oxide sludge or grit, becomes trapped inside the pump and prevents the internal motor from spinning. It can also be caused by the pump's internal components seizing up after long periods of inactivity or due to electrical failure within the pump itself.
This fault is frequently seen at the start of autumn when homeowners turn their heating back on after the pump has sat stationary throughout the summer months.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like F12 — no call-out fees, no surprises.
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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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