Installing A Cascading System; Connecting Water Supplies - Navien NPE-180A Installation Manual

4. Installing a Cascading System

When installing a cascading 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 cascading systems. Read them carefully before designing or installing the system.

4.1 Connecting Water Supplies

Several options are available for plumbing a cascading 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
cascading 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 heaters
Note
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.
Multiple NPE-S Units:
DHW Supply Line
36 Installing a Cascading System
Communication
Cable
Recirculation Line
[NPE-180A/ 210A/ 240A]
Communication
Cable
[NPE-180S/ 210S/ 240S]
Union
Ball Valve
Check Valve
Faucet
Expansion Tank
Pressure Relief Valve
Gas Supply Line
Cold Water Supply Line
Union
Ball Valve
Check Valve
Faucet
Expansion Tank
Pressure Relief Valve
Gas Supply Line
Cold Water Supply Line