Select your fault code
Sanju's Heating
Vaillant Guide
F.22Low Water Pressure
Your boiler has shut down for safety because the water pressure inside the system has dropped too low.
What F.22 means
Your boiler has shut down for safety because the water pressure inside the system has dropped too low.
Technical: Safety Switch-Off
Possible causes
- Low system water pressure (below 0.8 bar)
- Incorrect earth connection between cable harness and boiler
- Flow or return sensor (NTC) defective
- Fault in the cable or casing
- Black discharge via ignition cable, ignition plug or ignition electrode
Can you fix it yourself?
You can check the pressure gauge on the front of your boiler — if the needle is below 1.0 bar, the system needs repressurising. If you are not confident doing this yourself, or the pressure keeps dropping after topping up, there is likely a leak or a faulty sensor that needs a Gas Safe engineer.
Need a Gas Safe engineer?
Sanju's Heating covers Newbury, Basingstoke & Reading. Fast response, transparent pricing.
sanjusheating.co.uk/book