BoilerFaultCodesYour boiler is struggling to move heated water through the system effectively, which is causing it to stop for protection.
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
What causes this fault?
This fault occurs when the boiler detects that water is not moving through the internal pipework fast enough to carry heat away from the burner. The most common reasons are a failed internal pump that can no longer push the water, or a blockage caused by a build-up of debris and sludge within the system. Because the water stays still and overheats rapidly, the boiler shuts down to prevent damage to the heat exchanger.
This issue is most frequently seen during the first few cold days of autumn when the heating is turned back on after being idle all summer, which can cause internal pump parts to seize.
DIY fix possible
Check that all radiator valves are fully openEnsure the boiler pressure is between 1 and 1.5 bar on the gaugeBleed your radiators to remove any trapped air pockets
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A boiler cover plan would cover faults like E125 — 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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