Navien NFB-175H Installation Manual page 73

System Application #1- Cascade System with Closely Spaced Tees
●
Supply
Cold water
Backflow preventer
Expansion tank
Return
Connect the "SH Demand (SH T/T or Zone controller)" to the main unit.
Note
●
Connect the supply/return sensors to SUPPLY and RETURN terminals of the CNT1/2 terminal strip
●
on the main unit PCB.
Connect the outdoor sensor (optional) to the main unit.
●
Install system pumps to the units (main and sub) as required by the system configuration. When
●
configuring a cascade system, the output of the zone pumps installed at the main and sub units
are used as the output of the secondary system pump.
Connect zone pumps to the zone controller. Do not connect zone pumps to the main or sub units.
●
System Application #2- Cascade System with Hydro Separator
●
Return
Temperature
sensors (required)
Dirt collector
Hydro/Air separator
Connect the "SH Demand (SH T/T or Zone controller)" to the main unit.
Note
●
Connect the supply/return sensors to SUPPLY and RETURN terminals of the CNT1 terminal strip on
●
the main unit PCB.
Connect the outdoor sensor (optional) to the main unit.
●
Install system pumps to the units (main and sub) as required by the system configuration.
●
Connect zone pumps to the zone controller. Do not connect zone pumps to the main or sub units.
●
Air separator
Temperature
12" (30 cm)
sensors (required)
maximum
Supply
Main Sub1
Main
Sub1
Cold water
Backflow preventer
Expansion tank
Installing a Cascade System
Sub2
Sub2
73