Navien Backflow Damper (Back-Draft Damper) - Navien NFC-175 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 appliances are required to prevent exhaust
from entering the building.
Included Items
Backflow Damper
Installation Manual
Ready-Link
communication
cable
Screw (4 ea)
Specifications
Part Name
Part No.
Material
74 Installing a Common Vent System
Cond ensin
g Wate r Heat er
Co mm
on Ve nt
Ins tal lat Sy ste m
ion Ma
For NPE nu al
Seri es
Wat er
Hea ters
Certi ed
to ANSI Z21.10.3
Keep this manual – CSA 4.3. (Only
required . for future for U.S.
referenc e whenev installat ions)
er mainten
WARN ance or service
ING is
If the informa
injury, or death. tion in these instruct
ions is
- Do not store or not followe d exactly
- WHAT use gasolin , a re
TO DO IF YOU e or other ammab or explosi on may
Do not try to light SMELL GAS le vapors result, causing
Do not any applian and liquids propert y damage
Immed touch any electric ce. in the vicinity , persona
iately call al switch; of this or any l
If you cannot your gas supplie do not use any other applian
Installa reach your r from a neighb phone in your ce.
- tion and gas supplie or's phone. buildin g.
- This entire service must be r, call the re depart Follow the gas
mainte manua l must perform ed by ment. supplie
nance of the be left for the a quali ed installe r's instruc tions.
- The installa commo n vent consum r, service
ANSI Z223.1 tion must conform system . er. The consum agency or the
/NFPA 54. with local er must read and gas supplie
- When applica codes or, in the refer to this manua r.
Standa rd, Title ble, the installa absenc l for proper
24 CFR, Part 3280, tion must conform e of local codes, operati
Mobile with the the Nationa on and
Homes . Manufa ctured l Fuel Gas Code,
Home Constru
ction and
Safety
5.9" (150 mm)
1.1" (28 mm)
Backflow Damper
30014367A
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
Refer to "9.9 Maintenance" for detailed inspection procedures.

Navien Backflow Damper (Back-draft Damper)

Damper plate
Maintenance port
Gasket
Maintenance port cover
Fix screw