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Installing a Common Vent System
3. Connect the Common Vent Collar Kit to the
exhaust duct of the boiler unit.
4. Tighten the four mounting screws to secure the
Common Vent Collar Kit in place. The screws (x
4) are supplied with the Common Vent Collar Kit.
WARNING
If the original vent collar must be repaired or
reassembled, ensure that it is tightened by
using the 4 provided screws.
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.
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 NFB-H boiler unit:
1. Remove the screws from the exhaust vent
adapter.
2. Open the front cover.
Detach the exhaust vent adapter from the top
of the unit. Disconnect the Vent Installation
Detector (VID) wiring from the harness.
Summary of Contents for NFB-175H
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