Connecting The Communication Cables - Navien NHB Series Installation & Operation Manual

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
Flow Rate (GPM)
Qty
@ 20 °F ΔT
2 58
3 87
4 116
5 145
6 174
7 203
8 232
9 261
10 290
11 319
12 348
13 377
14 406
15 435
16 464
NFB-399C
Flow Rate (GPM)
Qty
@ 20 °F ΔT
2 76
3 114
4 152
5 190
6 228
7 266
8 304
9 342
10 380
11 418
12 456
13 494
14 532
15 570
16 608
Recommended
Boiler Pipe Sizes (2-4 ft/s)
2-1⁄2"
3"
4"
4"
5"
5"
5"
5"
6"
6"
6"
6"
6"
7"
7"
Recommended
Boiler Pipe Sizes (2-4 ft/s)
3"
3-1⁄2"
4"
5"
5"
5"
6"
6"
6"
7"
7"
7"
8"
8"
8"

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:
CNK1
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.
Installing a Cascade System 71