Pressure conditions in the system
Ideal arrangement of the fans
The left illustration shows the ideal arrangement of the fans (both on the suction side to the rotorsystem). If both fans are arranged on the suction side of the rotorsystem, then the proper difference between outdoor air and outgoing air is achieved. (see figure).
A functioning double purge sector ensures a practically complete separation of outdoor air and outgoing air.
The purge sector fulfils its function when the pressure potential of the outdoor air is greater than that of the outgoing air.A differential pressure of 200 - 500 Pa is best for the function of the purge sector.