Navien NHB-055 Installation & Operation Manual page 29

3.5.4 System Application - Air Handler System
Return filter
Air Separator
System Pump (Boiler Pump)
Make-up Water
Backflow preventer
Expansion Tank
Pressure reducing valve
Air Flow
Air Handler
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 24 for make-up water connections and refer to the requirements of your local codes
to ensure compliance.
Air handlers with an internal pump shall be piped either with a crossover pipe at the AHU or in a primary/secondary
configuration with the boiler.
Refer to the "3.6.6 Wiring Diagram - Air Handler" on page 34 for wiring connections.
You can use a secondary piping configuration for the air handler system to maintain optimal flow and heat capacity.
Installing the System Piping 29