BoilerFaultCodesYour boiler is struggling to move water around the system before it starts the heating process, which is often caused by a blockage or a pump issue.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Pre-circulation fault
What causes this fault?
This fault occurs when the boiler detects that water isn't moving through the unit quickly enough during its initial startup checks. The most common reasons are a build-up of sludge blocking the internal pipework or a mechanical failure of the pump that circulates the water. Because the water can't flow, the boiler shuts down to prevent the heat exchanger from overheating.
This issue often surfaces in autumn when the heating is turned back on after a long summer break, which can cause internal pump components to seize up from inactivity.
DIY fix possible
Check that your boiler pressure is between 1.0 and 1.5 bar on the pressure gaugeEnsure all radiator valves and boiler isolation valves are fully openGently bleed your radiators to remove any trapped air pockets
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A boiler cover plan would cover faults like E109 — 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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