Installation Sheet
15 Rinnai Rack Installation
MSB InstallaƟon
All of the water heaters should be electronically con‐
nected using the MSB control system. The only excep‐
on is when a water heater is dedicated to recovering a
tank. The MSB kits can electronically connect up to 25
water heaters.
When over 5 water heaters are connected together,
MSB‐M units are connected using MSB‐C2 kits.
If mulple MSB‐M are used, then at least three water
heaters should be connected to each MSB‐M. Example:
With 7 water heaters, one MSB‐M should control 4 wa‐
ter heaters and the other MSB‐M should control 3 wa‐
ter heaters.
The temperature seng for all of the connected water
heaters is controlled by the temperature controller
connected to the water heater with the master MSB
Board. Temperature controllers connected to the other
units will provide maintenance codes for their respec‐
ve units.
On applicable models a single MCC‐91 can be connect‐
ed to the master MSB Board to provide temperatures
greater than 140ºF for all the water heaters in the MSB
system.
M MSB-M control board
A Connector cable A (part of MSB-M kit; replace
with MSB-C3 cables for V Series)
C1 MSB-C1 cable (9.8 feet) for connecting water
heaters within a banked system (up to 5), (use
MSB-C3 cables for V Series)
C2 MSB-C2 cable (13.1 feet) for connecting MSB-M
control boards (up to 5)
In the diagram above, 25 water heaters are
electronically connected. Each bank of 5 is controlled
by an MSB‐M control board. These boards are
connected to each other with MSB‐C2 cables. One
MSB‐M is the controlling or master MSB‐M for the
enre system.
M
A
C2
C1
Water Heater
PC board