Vaillant aroTHERM fault F.22

What it means

Fault message F.22 appears alternately with the current filling pressure if the filling pressure of the heating installation falls below 0.05 MPa (0.5 bar) for longer than one minute. This is a blocking fault condition.

Likely causes

1. Failure to top up after M32 warning
2. Failure to top up water after prior low pressure warnings
3. Failure to top up after prolonged low pressure warning (M32)

Where to start

1. For multi-storey installations, ask competent person for adjusted required pressure
2. Select Yes to reset high-pressure switch fault after investigating and correcting cause
3. Navigate to High-pressure switch → Reset fault? and select Yes to clear the high-pressure switch fault