Starting The Common Vent System - Navien NPE Installation & Operation Manual

Maintenance Port
Navien Backflow Damper has a maintenance port to allow you to
easily inspect the operating condition of the damper plate.
Maintenance port
Refer to "5.9 Maintenance" for detailed inspection procedures.
Navien Backflow Damper (Back-draft Damper)
When using a common vent in a cascade system,
Note
backflow devices are required to prevent exhaust
from entering the building.
54 Installing a Common Vent System
Damper plate
Maintenance port
Gasket
Maintenance port cover
Fix screw

5.3 Starting the Common Vent System

5.3.1 Backflow Damper Assembly
Follow the instructions below to assemble the backflow damper
on the NPE water heater units:
1. Remove the screws from the exhaust vent adapter.
2. Detach the exhaust vent adapter.
3. Connect the backflow damper to the exhaust duct of the water
heater unit.