Navien NHB Series Installation & Operation Manual page 33

3.5.2 System Application - Zone System with Pumps (Primary/Secondary Piping)
Pressure
Relief Valve
Air Vent
Air Vent
Bushing
System application drawings are intended to explain the system piping concept only.
Note
Install a filter in the system return to remove foreign objects from the system. Foreign objects inside the system may result in
abnormal system operation.
Refer to "3.3 Filling the System" on page 29 for make-up water connections and refer to the requirements of your local codes
to ensure compliance.
Use a pump with an integral check valve or install a check valve at the pump outlet.
Refer to "3.6.6 Wiring Diagram - Generic Zone System with Circulators" on page 42 for wiring connections.
Depending on the installation environment, the supply top and return top piping option can be applied.
Return filter
Boiler Pump
Additional Zone
Air Separator
Pressure
Relief Valve
Air Vent Busing
Double Nipple
Tee
Supply
<Alternate Top Connections>
Zone #2
Zone #1
Backflow preventer
Pressure reducing valve
Expansion Tank
Return
Auto Air
vent
Installing the System Piping
Make-up Water
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