Navien NPN Installation & Operation Manual page 39

3.5.3 Measuring Vent Length (Indoor Models Only)
Refer to the table to find the maximum vent length based on the number of elbows. (Two 45 degree elbows
count as one 90 degree elbow.)
Vent type Diameter
3 in. / 5 in.
Concentric
(80 mm / 125 mm)
Number of 90° Elbows
0
1
2
3
4
Note
The Maximum Length does not include any elbows.
3.5.4 Terminating the Vent
Before installing the water heater, determine what type of vent termination is appropriate for the installation
location and situation. Examples in this section describe typical venting configurations, but they do not include
all possible options.
The following terminations can be used. Refer to the vent manufacturer's instructions for detailed installation
procedures.
Duravent, Inc. Venting Components
Refer to the contact information of the manufacturer if necessary:
Note
Manufacturer: Duravent
●
Tel: 800-835-4429
●
E-mail: customerservice@duravent.com
●
Website: www.duravent.com
●
38 Installing the Water Heater
Max number of 90° Elbows Max. Vertical and Horizontal (Total) Vent Length
4 43 ft (13 m)
Maximum vent length
43 ft (13 m)
38 ft (11.5 m)
33 ft (10 m)
28 ft (8.5 m)
23 ft (7.0 m)