Vaillant fault code F22

Dear All

Why did the boiler switch off and display fault code F.22? I don’t understand… Help please


Hi Josh,

Fault code F.22 means your boiler’s heating system has a low filling pressure and needs to be fixed because it can damage or burn the boiler. The bar graph display on the right side of the screen shows the pressure level, the normal pressure level should be between the dotted sections in the middle, the 0.1 to 0.2 MPa, where the heating system is cool.

However, if the level drops down to 0.8 MPa then it’s too low and the bar graph starts flashing. Within a minute, the maintenance sign, an open-ended spanner appears. It eventually drops to the lowest level, 0.5 MPa so the boiler shuts down and the display screen shows the F.22 code. In order to fix this issue, you must re-fill the heating system. When the system has a sufficient amount of water, the error code disappears after approx. 20 seconds.

The screen displays current filling pressure with the lowest and highest pressure level. Be sure to always check the pressure level and make sure it is moderated (topped with water). If the pressure keeps dropping, contact a heating specialist for further assistance.