Navien NFC-175 Installation & Operation Manual page 79

9.6.3 Direct Vent Application – Horizontal
Installation
In cases where a 12" horizontal clearance is not possible, provide a
vertical clearance of at least 36" with the exhaust above the intake
but do not exceed 20' .
i n .
m ) m
0 0 m
1 2 " ( 3
Exhaust Gas
Intake Air
Exhaust
Maximum
length 20'
(6 m)
Minimum
length 36"
Intake
(91 cm)
The illustration is intended for reference purposes
Note
●
only.
Direct the exhaust away from any building
●
openings.
During cold weather situations, the temperature of
●
the exhaust will be much warmer than the ambient
air. Therefore, you will see water vapor being
produced at the termination.
Installing a Common Vent System 79