Navien NFB-175H Installation Manual page 34

3.5.4 System Application - Air Handler System
Expansion Tank
System application drawings are intended to explain the system piping concept only.
Note
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Install a filter in the system return to remove foreign objects from the system. Foreign objects inside
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the system may result in abnormal system operation.
Refer to "3.3 Filling the System" on page 28 for make-up water connections and refer to the
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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
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primary/secondary configuration with the boiler.
Refer to the "3.6.9 Wiring Diagram - Air Handler" on page 45 for wiring connections.
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You can use a secondary piping configuration for the air handler system to maintain optimal flow
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and heat capacity.
34 Installing the System Piping
System Pump
(Boiler Pump)
Air Flow
Air Handler
Air Separator
Make-up Water
Backflow preventer
Pressure reducing valve