E109 High
Your boiler is struggling to move water around the system before it starts the ignition process, which is preventing it from firing up.
Technical description: Pre-circulation fault.
Typical repair cost: £120-£350 (including labour)
DIY fix possible
Check that the boiler pressure is between 1.0 and 1.5 bar on the gaugeIf pressure is low, use the filling loop to top it upEnsure all radiator valves and isolation valves under the boiler are fully openRestart the boiler using the reset button
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
- Water Pressure Sensor
- Main PCB
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