57
Installing a Cascade System
5.2.1 Configuring the Communication
Settings
After connecting the Ready-Link communication
cables, restore power to the water heater and turn
on all water heaters using the Power button.
To configure the communication settings:
1. On the Main water heater, press and hold the
Diagnostic
and
Up
(+) buttons for more than
5 seconds. “MA.00” will appear on the display to
confirm that this water heater is set as the Main.
2. On the Sub water heater, press and hold the
Diagnostic
and
Down
(-) buttons for more than
2 seconds. “SL.01” will appear on the display to
confirm that this water heater is set as the Sub.
3. On the Main water heater, press and hold the
Diagnostic
and
Up
(+) buttons for more than
5 seconds. The display screen on the configured
water heater will return to the temperature
display.
Note
To cancel the cascade
communication setup, on the Main
water heater, press and hold the
Diagnostic
and
Reset
buttons for
more than 5 seconds. The water
heater will revert to independent
operation. Repeat steps 1-3 to
reassign the Main water heater.
5.1.1 Piping Sizes and Considerations
When plumbing a cascade system, consider the
following pipe diameters and flow rates. Note that
flow rates above 6.6 ft/s may cause pipe erosion.
These specifications may vary depending on
installation conditions.
Qty
ΔT=54ºF
Flow rate
(GPM)
Water
Velocity
(ft/s)
Pipe
Diameter (mm/in)
1
6.02
4.38
20A
3
/
4
in
2
12.04
4.92
25A
1 in
Note
The table above is based on model
NHW700-199.
5.2 Connecting the
Communication Cables
Two water heaters can be connected with Navien
Ready-Link communication cables. Select one of
the water heaters in the cascade system as the
Main water heater, and then connect the other
water heater to it as the Sub. Before making any
connections, ensure that the power is turned off to
all water heaters.
Connect the Ready-Link cables to the J6 ports on
the right side of the front panel:
Summary of Contents for NHW700
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