Your boiler has detected that a internal pump protective cover is loose or has moved out of its correct position.
This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.
Technical description: Pump cover panel (17) back into place
What causes this fault?
This fault occurs when the protective internal casing around the main pump becomes dislodged or is not seated correctly during operation. The most common reason is vibration over time causing the housing clips to loosen, or the cover being bumped slightly during a previous service.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
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A boiler cover plan would cover faults like A1 — no call-out fees, no surprises.
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