F.22
Low water pressure in the system
Vaillant F.22 indicates low system water pressure or a related water-pressure/circulation issue.
What this code means
Vaillant F.22 indicates low system water pressure or a related water-pressure/circulation issue.
Possible causes
- System pressure below the normal range
- Water-pressure sensor problem
- Loose or faulty wiring to pump or pressure sensor
- Water-pressure sensor fault
- Pump issue on some open-vented boilers
- Internal expansion-vessel fault
Common symptoms
- Boiler stops or locks out
- F.22 displayed
- System pressure may be below 1 bar
Checks to make
- Check the system pressure
- If pressure is below 1 bar and you are competent to do so, follow the Vaillant/manual procedure to repressurise the system to the specified range
- If pressure is normal or the fault returns, arrange professional diagnosis
Safety
- Do not remove the boiler casing or work on internal gas, combustion or electrical components unless appropriately qualified.
Model notes
Vaillant states the normal system pressure range is typically around 1 to 1.5 bar; always follow the specific appliance manual.