61Installing 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 boiler. The following sections describe additional considerations that are
specific to installing cascade systems. Read them carefully before designing or installing the system.
8.1 Connecting Water Supplies
Several options are available for plumbing a cascade system of boilers. 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 boilers to meet high-volume heating demands. Some possible connection options include the following:
●
Example of a Basic Cascade System Application
12” (30 cm)
maximum
Air separator
Sub2
Sub1
Main
Temperature
sensors (required)
Cold water
Supply
Return
Back flow preventor
Expansion tank
[NFB-175/200]
Note
●
System application drawings are intended to explain the system piping concept only.
●
Install a filter in the system return to remove foreign objects from the system. Foreign objects inside the system may result in
abnormal system operation.
●
Refer to “3.3 Filling the System” on page 27 for make-up water connections and refer to the requirements of your local codes
to ensure compliance.
●
Use pumps with integral check valves or install check valves at the pump outlets.
●
Navien system supply (Included box)/return (Accessory) Temperature sensor must be installed for cascade system operation.
●
Adjust the settings at the main unit as the cascade system uses only the main unit settings. Changes made to the sub units are
ignored.
●
Refer to ““Configuring a Cascade System” on page 93 to make adjustments to the boiler staging settings. By default, boilers
will be added to the system when the input capacity exceeds 70%, and removed when the input capacity falls below 30%.
8. Installing a Cascade System
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