BoilerFaultCodesYour heat pump's engine has stopped turning unexpectedly, which means the system cannot currently generate heat for your home.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Compressor Stall Error
What causes this fault?
This fault occurs when the main pump inside the unit attempts to start but is physically prevented from turning or maintaining its rhythm. The most common reasons are a mechanical failure within the pump itself, an electrical fault in the control board, or an issue with the components that provide the initial power boost to get the system running.
This issue is more frequent during the first cold snaps of autumn or winter when the system is required to work harder after long periods of inactivity.
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 J52 — 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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