In the Service Menu of the unit, I can only adjust the Extract fan speed for the 3 modes Minimum + Medium + Maximum. The Supply fan speed is for all 3 modes, is automatic adjusted according to the Supply/Extract ratio that is set in the ‘Standard (%)’, when I change the Extract fan speed.
In the Service Menu, the only thing I can adjust for Overpressure, is the Duration.
What I want, is to change the Supply/Extract ratio for the Overpressure mode, so when our extraction hood in the kitchen is running (or when we use the fire stove in the living room), the HERU blows significant more air in the house, than it extracts, creating the right pressure balance for the extraction hood to work 
