Navien NFC-250/175H Installation Manual page 77

Concentric Sidewall Venting
●
Combustion Air Intake
Exhaust
Gas
Maintain 12" (300 mm) min. clearance above highest
anticipated snow level or grade, whichever is greater
Concentric Vertical Venting
●
Exhaust Gas
Combustion
Air Intake
For cascade applications, the required
Note
horizontal clearance between
terminations is 12" for both sidewall and
vertical venting installations.
Combustion Air Intake
Exhaust
Gas
1" (25 mm) min.
Maintain 12" (300mm) min.
clearance above highest
anticipated snow level or
grade, whichever is greater
(maximum of 24" above roof)
Do not vertically stack
concentric terminations
on sidewalls.
Indoor Boiler Installation Venting
Examples (Continued)
Low Profile Two-Pipe Sidewall Venting*
●
Exhaust
Intake Air
(from
(from outdoors)
appliance)
Exterior View
* IPEX and Centrotherm Low Profile terminations
only
** Clearance above highest anticipated snow level
or grade, or as required by local codes, whichever
is greater
Only the following orientations are
Note
allowed for twin pipe terminations.
Venting for Combustion Air 77