118 High
Your boiler has detected that the water pressure is too low for it to operate safely, or it is struggling to move water through the system.
Technical description: Pressure less than 1 bar or pump pressure increase too low (no pump detection).
Typical repair cost: £0-280 (including labour)
DIY fix possible
Check the pressure gauge on the front of the boiler; it should ideally be between 1.2 and 1.5 bar.Locate the filling loop (usually a silver braided hose with small black lever valves) underneath the boiler.Slowly open the valves to let water in until the gauge reaches 1.5 bar, then ensure they are closed tightly.Press the Reset button on the control panel to clear the fault.
Protect yourself from future repair bills
A boiler cover plan would cover faults like 118 — no call-out fees, no surprises.
*Affiliate links — we may earn a commission at no extra cost to you. Prices shown are starting prices.
Parts commonly replaced
- Circulation pump
- Water pressure sensor
- Automatic air vent
*Affiliate links — we may earn a commission at no extra cost to you.