Installing A Cascade System; Connecting Water Supplies - Navien NPE Installation & Operation Manual

4. Installing a Cascade System

When installing a cascade system, carefully consider the design of the system and the features of the installation location. Follow all local
codes and regulations, as well as all guidelines for installing the water heater. The following sections describe additional considerations that
are specific to installing cascade systems. Read them carefully before designing or installing the system.

4.1 Connecting Water Supplies

Several options are available for plumbing a cascade system of water heaters. The options shown here are only examples. The setup you
choose will vary based on the installation location, local building codes, and other factors. Follow all applicable regulations when installing a
cascade system.
You can connect up to 16 water heaters to meet high-volume hot water demands. Some possible connection options include the following:
Recirculation via Internal Pumps ("A" model only):
DHW Supply Line
The recommended minimum recirculation flow rate for each water heater is 2 GPM. Depending on the number of water
Note
heaters and the diameter of the recirculation line, it may not be necessary to connect all water heaters to the recirculation line.
If this is the case, set the unconnected water heaters to internal recirculation mode. The master water heater must always be
connected to the recirculation line and set to external recirculation mode.
Each unit must be configured for cascade operation.
System sensors are required for proper operation of the cascade system.
Multiple NPE-S Units:
DHW Supply Line
46 Installing a Cascade System
Communication
Cable
Recirculation Line
[NPE-180A/ 210A/ 240A]
Communication
Cable
[NPE-150S/ 180S/ 210S/ 240S]
Union
Ball Valve or Navien Plumb Easy Valve
Check Valve
Faucet
Expansion Tank
Pressure Relief Valve
Gas Supply Line
Cold Water Supply Line
Union
Ball Valve or Navien Plumb Easy Valve
Check Valve
Faucet
Expansion Tank
Pressure Relief Valve
Gas Supply Line
Cold Water Supply Line