BoilerFaultCodesYour boiler is struggling to move water around the system effectively, 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: Poor circulation
What causes this fault?
This fault occurs when the boiler detects that water is not flowing through the internal pipework quickly enough to carry heat away. The most common reasons are a pump that has seized up or a build-up of sludge and debris that is physically blocking the narrow passages inside the main heat exchanger.
This issue often surfaces in autumn when the heating is turned back on after a long summer break, as stagnant debris can settle and cause the pump to seize.
DIY fix possible
Check that the boiler pressure is between 1 and 1.5 bar on the pressure gauge.Ensure all radiator valves and internal stop taps are fully open.Gently bleed your radiators to remove any trapped air pockets.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like E109 — 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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