Starting The Common Vent System - Navien NFB-175 Mode D'emploi

9.3 Starting the Common Vent System

9.3.1 Backflow Damper Assembly
Follow the instructions below to assemble the backflow damper
on the NFB boiler unit:
1. Remove the screws from the exhaust vent adapter.
2. Detach the exhaust vent adapter.
72 Installing a Common Vent System
3. Connect the backflow damper to the exhaust duct of the boiler
unit.
4. Tighten the four mounting screws to secure the backflow
damper in place. The screws (x 4) are supplied with the
backflow damper.