Navien NFB-301C User Manual

77Installing a Common Vent System
9.2 Navien Backflow Damper (Back-draft
Damper)
The Navien backflow damper prevents backflow (back-draft) at the
exhaust vent while the boiler unit operates.
By closing the exhaust vent as soon as the combustion cycle ends,
the Navien backflow damper retains heat in the system for longer
periods. This improves the system’s thermal efficiency.
Note
When using a common vent in a cascade system,
backflow devices are required to prevent exhaust
from entering the building.
Included Items
Backflow Damper
Installation Manual
Con
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ens
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W
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H
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Common Vent System
Installation Manual
Fo
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Co
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W
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H
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Common Ven
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System
Installati
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Fo
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.
Ready-Link
communication
cable
Screw (4 ea)
Specifications
8.1” (206 mm)
3” (76 mm)
1.6” (42 mm)
Part Name Backflow Damper
Part No. 30022799A
Material PP (Polypropylene)
Maintenance Port
Navien Backflow Damper 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 “9.9 Maintenance” for detailed inspection procedures.
Navien Backflow Damper (Back-draft Damper)
Note
When using a common vent in a cascade system,
backflow devices are required to prevent exhaust
from entering the building.

Navien NFB-301C Specifications

General

Brand	Navien
Model	NFB-301C
Category	Boiler
Language	English