Navien NFB-175 Mode D'emploi page 62

System Application #1- Cascade System with Closely Spaced Tees
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Cold water
Back flow preventor
Connect the "SH Demand (SH T/T or Zone controller)" to the main unit.
Note
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Connect the supply/return sensors to SUPPLY and RETURN terminals of the CNT1/2 terminal strip on the main unit PCB.
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Connect the outdoor sensor (optional) to the main unit.
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Install system pumps to the units (main and sub) as required by the system configuration.
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System Application #2- Cascade System with Hydro Separator
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Return
Dirt collector
Connect the "SH Demand (SH T/T or Zone controller)" to the main unit.
Note
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Connect the supply/return sensors to SUPPLY and RETURN terminals of the CNT1 terminal strip on the main unit PCB.
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Connect the outdoor sensor (optional) to the main unit.
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Install system pumps to the units (main and sub) as required by the system configuration.
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Connect zone pumps to the main unit, or to the zone controller.
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62 Installing a Cascade System
Supply
Air separator
Expansion tank
12" (30 cm)
Temperature
maximum
sensors (required)
Return
Supply
Temperature
sensors (required)
Hydro/Air separator
Sub1
Main
Main
Sub1
Cold water
Back flow preventor
Expansion tank
Sub2
Sub2