E109 High
Your boiler is struggling to move water around the system properly, which is causing it to overheat and shut down for safety.
Technical description: Poor circulation
Typical repair cost: £150-£350 (including labour)
DIY fix possible
Check that your boiler pressure gauge is between 1 and 1.5 barEnsure all radiator valves and the external isolation valves under the boiler are fully openGently bleed your radiators to remove any trapped air pockets
Protect yourself from future repair bills
A boiler cover plan would cover faults like E109 — no call-out fees, no surprises.
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Parts commonly replaced
- Central heating pump
- Main heat exchanger (de-scaling)
- Flow/Return thermistors
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