F9 High
Your boiler has detected an issue with the sensor that monitors water pressure, which means it cannot verify if there is enough water to run safely.
Technical description: Water pressure sensor fault
Typical repair cost: £140-230 (including labour)
DIY fix possible
Check the pressure gauge on the front of the boiler; it should be between 1.0 and 1.5 bar.If the pressure is too low, use the filling loop underneath the boiler to carefully top it up.Press the reset button (usually marked with a flame or 'reset') once the pressure is corrected.
Protect yourself from future repair bills
A boiler cover plan would cover faults like F9 — no call-out fees, no surprises.
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Parts commonly replaced
- Water pressure sensor
- Pressure relief valve
- Wiring harness
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