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

8.1.1 Piping Sizes and Considerations
When plumbing 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-175
Flow Rate (GPM)
Qty
@ 20°F ΔT
2 32.2
3 48.3
4 64.4
5 80.5
6 96.6
7 112.7
8 128.8
9 144.9
10 161
11 177.1
12 193.2
13 209.3
14 225.4
15 241.5
16 257.6
NFB-200
Flow Rate (GPM)
Qty
@ 20°F ΔT
2 36.6
3 54.9
4 73.2
5 91.5
6 109.8
7 128.1
8 146.4
9 164.7
10 183
11 201.3
12 219.6
13 237.9
14 256.2
15 274.5
16 292.8
Recommended
Boiler Pipe Sizes (2-4 ft/s)
2"
2-1/2"
3"
3"
3-1/2"
3-1/2"
4"
4"
4"
5"
5"
5"
5"
5"
6"
Recommended
Boiler Pipe Sizes (2-4 ft/s)
2"
2-1/2"
3"
3-1/2"
3-1/2"
4"
4"
5"
5"
5"
5"
5"
6"
6"
6"

8.2 Connecting the Communication Cables

Up to 16 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:
SUPPLY RETURN OUTDOOR
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.
Refer to "11.4.4 Configuring a Cascade System" to configure the
communication settings.
NC
NC
NC
COM
NC
NC
COM
NC
NC
COM
NC
NC
COM
NC
NC
COM
NC
LWCO
COM
AC24VL
LWCO
AC24VN
AC24VL
AC24VN
C
W
R
C
W
R
C
W
R
C
W
DHW TANK
R
Installing a Cascade System 65