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Installing a Common Vent System
9.3 Starting the Common Vent
System
9.3.1 Common Vent Collar Kit Assembly
Follow the instructions below to assemble the
Common Vent Collar Kit on the NHB-H boiler unit:
1. Remove the screws from the exhaust vent
adapter.
2. Detach the exhaust vent adapter from the top
of the unit. Disconnect the Vent Installation
Detector (VID) wiring from the harness.
Maintenance Port
Navien Common Vent Collar Kit has a maintenance
port to allow you to easily inspect the operating
condition of the damper plate.
Maintenance port
Damper plate
Maintenance port
Gasket
Maintenance port cover
Fix screw
Refer to “9.8 Maintenance” for detailed inspection
procedures of the Navien Common Vent Collar Kit
(Back-draft Damper).
Note
When using a common vent in a
cascade system, backflow devices
are required to prevent exhaust from
entering the building.