Cascade System - Recirculation System Application Example - Navien NFC-175 Installation & Operation Manual

8.2 Cascade System - Recirculation System Application Example

When using the cascade system, external recirculation can only be connected to and controlled by the NPE "A" water heater. Set each
individual water heater to the appropriate recirculation mode utilizing the 2-way valve and front panel DIP switches. Refer to the NPE
Installation Manual for additional details.
If Recirculation Return Line Is Installed
Connect the domestic hot water return line to the desired number of NPE "A" water heaters. Set each unconnected NPE "A" water heater to
Internal Recirculation Mode. The NFC boiler should be set to Combi Pre-heat Mode.
Pressure
Relief Valve
Heating
Supply
Pump
Air Separator with
Expansion Tank
Optional System
Temperature Sensors
Heating Return
Note
A HotButton and Aquastat cannot be used for cascade systems.
Air Vent
Pressure
Relief Valve
Hydronic
Feed
Expansion
Water
Tank
NaviClean
<NPE-A> <NPE-A>
Sub1 Sub2
<NPE-S>
Sub3
Ball Valve
Check Valve
Faucet
Installing a Cascade System
Domestic
Cold Water
Supply
65