Navien NHB-055 Installation & Operation Manual page 54

System Application #5- Cascade System with DHW Indirect Tank (for Low DHW Demand)
DHW
Indirect
tank
Aquastat
Cold water
In this configuration, space heating and DHW can operate simultaneously.
Note
The aquastat on the DHW indirect tank must be connected to a slave unit.
If a dedicated slave unit is used, the input capacity requirement of the indirect tank shall not exceed the capacity of the single
boiler.
Connect the DHW pump to the slave unit.
System Application 6 - Cascade System with DHW Indirect Tank (for Low DHW Demand)
DHW
Indirect
Aquastat
Cold water
In this configuration, space heating and DHW can operate simultaneously.
Note
The aquastat on the DHW indirect tank must be connected to a slave unit.
If a dedicated slave unit is used, the input capacity requirement of the indirect tank shall not exceed the capacity of the single
boiler.
Connect the DHW pump to the slave unit.
54 Installing a Cascade System
Slave2 Slave1
tank
Slave2
Cold water
Master
Slave1 Master
Back flow preventor
Expansion tank
Air separator
Expansion tank
Temperature
12" 30 cm
sensors (required)
maximum
Supply
Temperature
sensors (required)
Hydro/Air separator
Supply
Cold water
Back flow preventor
Return
Return
Dirt collector