E109 High
Your boiler is struggling to move heated water through the system, causing it to shut down to prevent overheating.
Technical description: Poor circulation
Typical repair cost: £100-£350 (including labour)
DIY fix possible
Check that the boiler pressure is between 1.0 and 1.5 bar on the gaugeEnsure all radiator valves are fully openBleed 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
- Circulation pump
- Main heat exchanger
- System filter
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