BoilerFaultCodesYour boiler is struggling to circulate water properly after turning off the heating, which is likely caused by a blockage or a pump issue.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Heating mode – pump overrun error
What causes this fault?
This fault occurs when the boiler's internal sensors detect that water isn't moving through the system quickly enough after the flames have gone out. The most common reasons are a failing circulation pump that can't push the water anymore, or a blockage caused by a build-up of sludge and debris in the pipework. Small mechanical parts like the check valve can also become stuck, physically preventing the water from flowing away from the heat exchanger.
This issue often surfaces in autumn when the heating is turned back on after a long summer break, as internal pump parts can seize up from lack of use.
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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