71Installing a Cascade System
8.2 Connecting the Communication Cables
Up to 32 boilers can be connected with Navien Ready-Link
communication cables. Select one of the boilers in the cascade
system as the main boiler, and then connect the other boilers to
it as sub boilers. Before making any connections, ensure that the
power is turned off to all boilers.
Connect the Ready-Link cables to the CNK1 terminal strip on the
PCB:
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8.2.1 Configuring the Communication Settings
After connecting the Ready-Link communication cables, restore
power to the boiler and turn on all boilers using the Power button.
To configure the communication settings, refer to “11.6.4
Configuring a Cascade System” on page 103.
8.1.1 Piping Sizes and Considerations
When configuring a cascade system, consider the following pipe
diameters and flow rates. Note that flow rates above 4 ft/s may
cause pipe erosion or velocity noise. These specifications may vary
depending on installation conditions.
NFB-301C
Qty
Flow Rate (GPM)
@ 20 °F T
Recommended
Boiler Pipe Sizes (2-4 ft/s)
2 58 2-⁄"
387 3”
4 116 4”
5 145 4”
6 174 5”
7 203 5”
8 232 5”
9 261 5”
10 290 6”
11 319 6”
12 348 6”
13 377 6”
14 406 6”
15 435 7”
16 464 7”
NFB-399C
Qty
Flow Rate (GPM)
@ 20 °F T
Recommended
Boiler Pipe Sizes (2-4 ft/s)
276 3”
3 114 3-⁄”
4 152 4”
5 190 5”
6 228 5”
7 266 5”
8 304 6”
9 342 6”
10 380 6”
11 418 7”
12 456 7”
13 494 7”
14 532 8”
15 570 8”
16 608 8”