BoilerFaultCodesYour boiler is struggling to move water around the system correctly, which is causing it to shut down to prevent overheating.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Primary circulation fault or pump failure
What causes this fault?
This fault occurs when the water inside the boiler gets too hot too quickly because it isn't being pushed away into your radiators or hot water tank. The most common reason is that the internal pump has failed or is physically jammed, but it can also be caused by a build-up of sludge blocking the pipework or an airlock trapped in the system.
This issue is frequently seen in autumn when heating systems are switched back on after being idle all summer, which can cause the pump to seize.
DIY fix possible
Check that your radiator valves are openEnsure your boiler pressure is between 1.0 and 1.5 bar on the pressure gaugeGently bleed your radiators to remove trapped air
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A boiler cover plan would cover faults like 125 — no call-out fees, no surprises.
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Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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