Backflow preventer

The backflow preventer(s) prevent anything that is not wanted from flowing through a shut-down ventilation unit. They close automatically as soon as the fans come to a stop. The backflow preventers are used in the exhaust sockets of fans.

NOTICE: The backflow preventer must close autonomously through the force of gravity, regardless of the unit’s installation position.

  1. Disconnect ventilation unit from power supply.
  2. Open ventilation unit (take off front cover and housing cover).

Installing backflow preventer for supply air

  1. Remove EPP cover of supply air fan.
  2. Install backflow preventer such that it closes autonomously.
  3. Refit EPP cover of supply air fan.

Installing backflow preventer for outgoing air

  1. Remove cable with plug on outgoing air fan.
  2. Loosen fan screws (x3) and remove fan.
  3. Install backflow preventer in outgoing air channel such that it closes autonomously.
  4. Insert outgoing air fan and secure with the 3 screws.
  5. Connect cable with plug.
  6. Close ventilation unit.
  7. Switch supply voltage on, perform a function test.