F.22 High
Your boiler has detected that there is not enough water pressure in the system to operate safely, causing it to shut down to prevent overheating.
Technical description: Dry fire / Low water in system / Overheat
Typical repair cost: £0-180 (including labour)
DIY fix possible
Locate the silver braided filling loop hoses underneath or near the boiler.Open the two small valves on the filling loop to allow water into the system.Watch the pressure gauge on the front of the boiler until it reaches between 1.0 and 1.5 bar, then close both valves tightly.
Protect yourself from future repair bills
A boiler cover plan would cover faults like F.22 — 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
- Filling loop
- Pressure sensor
- Expansion vessel
*Affiliate links — we may earn a commission at no extra cost to you.