Navien NFB Series User Manual

63Installing a Cascade System
●
System Application #3- Cascade System with DHW Indirect Tank (for High DHW Demand)
12” (30 cm)
maximum
Sub2
Sub1
Main
Temperature
sensors (required)
Cold water
Supply
Return
Back flow preventor
Expansion tank
Cold water
DHW
Indirect tank
Aquastat
Air separator
Note
●
In this configuration, the full capacity of all boilers will be prioritized to the DHW demand.
●
The aquastat on the DHW indirect tank must be connected to the main unit.
●
Connect the DHW pump to the main unit.
●
System Application #4- Cascade System with DHW Indirect Tank (for High DHW Demand)
Sub2Sub1
Main
Cold water
Supply
Indirect tank
Aquastat
Cold water
DHW
Return
Dirt collector
Hydro/Air separator
Back flow preventor
Expansion tank
Temperature
sensors (required)
Note
●
In this configuration, the full capacity of all boilers will be prioritized to the DHW demand.
●
The aquastat on the DHW indirect tank must be connected to the main unit.
●
Connect the DHW pump to the main unit.

Navien NFB Series Specifications

General

Type	Condensing Boiler
Fuel Type	Natural Gas or Propane
Heat Exchanger	Stainless Steel
Vent Type	Direct Vent
Vent Diameter	2" or 3"