Navien NHB Series Installation & Operation Manual page 60

Indoor Boiler Installation Venting Examples (continued)
Non-Concentric Sidewall Venting - Air is drawn from a different
location that is at least 12 in (300 mm) away from the exhaust
termination. The exhaust termination can be located either on
the sidewall or roof. Try to minimize the length of the intake air
pipe when installing the vent.
* 12" (300mm) above the highest anticipated snow level, or as
required by local codes, whichever is greater.
Concentric Sidewall Venting
Combustion Air
Vent
60 Venting the Boiler
Combustion Air
Vent
Maintain 12"
(300 mm)
1" (25 mm) min.
min. clearance
above highest
anticipated snow
level or grade,
whichever is
greater.
Indoor Boiler Installation Venting Examples (continued)
3 in or 4 in Two-pipe Vertical Venting – Intake and exhaust pipes
do not have to terminate in the same area.
36" (900 mm) min.
Intake Air
Concentric Roof Venting
Vent
Combustion Air
Vent
Exhaust Gas
12" (300 mm) min
From any
obstruction
(above, below,
left, or right)
Maintain 12" (300mm) min.
clearance above highest
anticipated snow level or grade,
whichever is greater (maximum
of 24" above roof)
Combustion Air