High Lockout
F12 on Ideal Logic Max System

Your boiler's internal pump has stopped spinning, which means hot water cannot be moved around the system to heat your home or taps.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 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 is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

F1View →L2View →

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