Common Venting - Navien NPE-180A Service Manual

9.6 Common Venting

Model : NPE-150S, 180A, 180S, 210A, 210S, 240A, 240S
When cascading the water heaters with other Navien water
heaters, you can install a common venting system. Do not use
common venting if the water heater is used in a cascading system
with other manufacturer's water heaters. Include a condensate
drain in the main trunk as illustrated in the following examples.
Venting the Exhaust Only (Non-Direct)
●
H
Cap
Intake
Venting Intake and Exhaust to the Same Location
●
Intake
12" (300mm) min.
Cap
156 NPE Service Manual
Exhaust
D
W
Condensate
Drain
36" (900mm) min.
Exhaust
12" (300mm) min.
Condensate
Drain
Venting Intake and Exhaust to Dierent Locations
●
Cap
To determine the size of a common vent:
1. Add the BTU/H input ratings for each water heater in the
cascading system to determine the total BTU/H rating.
2. Determine the total length (L) of the common vent, which
consists of the horizontal width (W) and the vertical height (H):
Total length (L) = W + H.
H
W
Cap
Intake
3. Refer to the common vent table that follows to determine the
minimum length required for the common vent, based on the
total BTU/H rating, and the diameter of the vent pipe.
NOTE
For each short radius elbow that will be used in the vent, add 8
feet (2.4 m) to the total length. For each long radius elbow that
will be used in the vent, add 5 feet (1.5m) to the total length.
Exhaust
Intake
Condensate
Drain
Exhaust
D
Condensate
Drain
Version 2.21