Navien Backflow Damper (Back-Draft Damper) - Navien NHB Series Installation & Operation Manual

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.
When using a common vent in a cascade system,
Note
backflow devices are required to prevent exhaust
from entering the building.
Included Items
Backflow Damper
Installation Manual
Ready-Link
communication
cable
Screw (4 ea)
Specifications
3" (76 mm)
Part Name Backflow Damper
Part No. 30022799A
Material PP (Polypropylene)
Cond ensin
g Wate
Co mm r Heat er
on Ve nt
Ins tal lat
Sy ste m
ion Ma
For NPE nu al
Seri es
Wat er
Cond ensin Hea ters
g Wate
r Heat er
Co mm
on Ve nt
Ins tal lat
Sy ste m
ion Ma
For NPE
nu al
Seri es Certified to ANSI
Wat er Keep this Z21.10.3 – CSA
Hea ters required manual for future 4.3. (Only
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WARN ance or service
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Home Constru
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Safety
8.1" (206 mm)
1.6" (42 mm)
Maintenance Port
Navien Backflow Damper has a maintenance port to allow you to
easily inspect the operating condition of the damper plate.
Maintenance port
Maintenance port
Refer to "9.9 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.
Damper plate
Gasket
Maintenance port cover
Fix screw
Installing a Common Vent System 77