Installing A Cascade System; Connecting Water Supplies - Navien NPE-180A2 Installation 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 32 water heaters to meet high-volume hot water demands. Some possible connection
options include the following:
Recirculation via Internal Pumps ("A2" model only):
●
DHW Supply Line
The recommended minimum recirculation flow rate for each water heater is 2 GPM. Depending
Note
●
on the number of water 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 main water heater must always be connected to the
recirculation line and set to external recirculation mode.
Each unit must be configured for cascade operation.
●
60 Installing a Cascade System
Communication
Cable
Recirculation Line
[NPE-180A2/ 210A2/ 240A2]
Union
Ball Valve or Navien
Plumb Easy Valve
Check Valve
Faucet
Expansion Tank
Pressure Relief Valve
Gas Supply Line
Cold Water Supply Line