Navien NHB Series, Installation & Operation Manual

Page: 68 / 135

68 Installing a Cascade System
Ɣ System Application #3 - Cascade System with Zone Pump Control
Sub2 Sub1 Main
Cold water
Supply
Supply
Return Return
Supply
Return
Dirt collector
Hydro/Air separator
Back flow preventor
Expansion tank
Temperature
sensors (required)
Note
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Both the main unit and sub units use zone pumps for this application. To enable this feature, tap the Control button ( ) > SH Control
and set the Zone Setting to “OFF.”
Ɣ
Connect the zone pump to the main unit or subunit, and connect the “SH Demand (SH T/T)” to the zone that the pump is
connected to.
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Connect the supply/return sensors to SUPPLY and RETURN terminals of the CNT1/CNT2 terminal strip on the main unit PCB.
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Connect the outdoor sensor (optional) to the main unit.
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Depending on the installation environment, the supply top and return top piping option can be applied.
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Multi-zone temperature function is not available for this application.