109 Emergency
Your boiler has shut down because the internal water pressure has become too high, which could potentially cause leaks or damage if not addressed.
Technical description: Pressure > Pmax error
Typical repair cost: £80-220 (including labour)
DIY fix possible
Check that the filling loop valves are tightly closed.Locate a radiator bleed valve and use a key to release water into a cloth or bowl.Monitor the pressure gauge until it drops back into the green zone (typically 1.0 to 1.5 bar).
Protect yourself from future repair bills
A boiler cover plan would cover faults like 109 — no call-out fees, no surprises.
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Parts commonly replaced
- Filling loop valve
- Expansion vessel
- Pressure relief valve
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