BoilerFaultCodesYour boiler is having trouble moving hot water through the internal pipes, which usually means the circulation pump cannot start or is stuck.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Hot water circulation pump
What causes this fault?
This fault occurs when the boiler's internal pump fails to spin, meaning heated water cannot be moved toward your radiators or hot water tank. The most common reason is that the pump has become physically seized by a buildup of sludge or debris, or the electrical components inside the pump have reached the end of their lifespan.
This issue is frequently seen in autumn when the heating is turned back on for the first time after being idle all summer, which allows debris to settle and seize the pump.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like D.13 — 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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