Navien NPE-180A2 Installation Manual page 22

Typical Propane Gas piping examples:
Gas Regulators
(2 Stage)
High
Pressure
Regulator
Gas Tank
[2 Stage System with Multiple Regulators
(Recommended)]
22 Installing the Water Heater
Low Pressure
Regulator
(before entering
home or
building)
Gas Tank
Full Size
Gas Pipe
Note
Gas Regulator
12 in. W.C.
Full Size
Gas Pipe
Pipe
[Single Regulator System]
If installation requires the use of
gas pressure regulators, follow all
regulator manufacturers requirements
and recommendations for sizing and
proper installation.
Full size
Gas Pipe