Navien NPE-180A2 Installation Manual page 78

H
W
End Cap
Unit Unit
1 2
Siphon Loop Drain Hose
Drain
Common Vent Length Table
[Total Length (L) = W + H]
Vent Length for NPE Water Heater Units
Required
Model
Load
(Total
NPE-240A2/S2 D=3" D=4" D=6" D=8"
BTU/H)
399,800 2
599,700 3
799,600 4
999,500 5
1,199,400 6
1,399,300 7
1,599,200 8
1,799,100 9
1,999,000 10
2,198,900 11
2,398,800 12
Every 90° elbow used is equivalent to
Note
●
8 linear feet (2.4 m) of vent length.
The maximum equivalent length of
●
the branch pipe from the unit to the
common vent trunk is 16 equivalent feet.
Branch pipe lengths are not added
●
to the allowable equivalent vent
lengths that are provided in the
following charts.
78 Installing a Common Vent System
Exhaust
D
Unit
Intake
12
Total Length (ft)
60 106 200
40 71 160
30 53 120
42 96 150
35 80 142
30 68 121
60 106
53 94
48 85
43 77
40 71
Example of a Typical Installation
(Direct & Non-Direct Vent)
The following illustration depicts an example of a
common vent system installed for a cascade system
of 12 Navien NPE heater units.
Unit 1 Unit 2 Unit 12
Unit 1 Unit 2 Unit 12
[Direct Vent]
Maximum
length 20'
(6 m)
Minimum
length 36"
(91 cm)