Kit Components
MSB-M (Pack A)
(For wiring Units 1 and 2)
Parts List
Part
Qty
Control Board
Communication Cable A
Communication Cable B
Cable tie bracket
2
Cable tie
2
Instruction Sheet
1
MSB-C1 (Pack B)
(For wiring Units 3, 4 and 5)
Parts List
Part
Qty
Communication Cable B
Cable tie bracket
2
Cable tie
2
Instruction Sheet
1
Note: One MSB-C1 is required
for each water heater (Units 3, 4,
For Unit 1:
1) Remove the screw from the
sheet metal reinforcement plate
located at the bottom of the
water heater cabinet, and then
use it to secure the Control Board
to the water heater cabinet.
2) Connect the connector
from Communication Cable A (18
inch, 450 mm cable) to socket No. 1
on Control Board.
1
1
1
1
and 5)
3) Connect the connector from
Communication Cable A to the
4-pin socket located at the top of
the water heater control board.
Communication Cable A
ground wire terminal should be
grounded with the PC board
ground wire.
4) Attach the cable tie bracket to
the bottom of the water heater
cabinet using the existing screw.
Loosely secure the cable tie
through the bracket and around
the communication cable. DO NOT
TIGHTEN THE CABLE TIE AT THIS
TIME - the Communication Cables B
from the other water heaters must
be secured by this cable tie.
Communication Cables B
Water Heater
Control
Communication Cable A
Control Board
MSB Communication cable (MSB-C2)
bracket
1
If installing on a condensing
water heater, refer to the addi-
tional instruction showing
below. *
(18 in, 450 mm)
(9.8 ft, 3 m)
(9.8 ft, 3 m)
Screw
2
U306-1030(00)
Manifold Electronic Control System
Installation Instructions
MSB-M
MSB-C1
Note:
•
Up to 5 water heaters can be connected together using
the MSB-M and MSB-C1 kits.
United States & Canada: For use with Rinnai Tankless Water
Heaters (except for models V53e, V53i and R63LSe which must
use pressure activation valves, PVA).
•
Disconnect all water heaters from their power source before carrying out
the following installation procedures.
NOTE: The front cover panels of each water heater must be removed prior
to completing the following installation procedures.
WARNING
Please contact Rinnai if you have further questions on the
applicable water heater models.
•
•
When over 5 water heaters are connected together,
MSB-M units are connected using MSB-C2 kits.
•
Master
2nd
3rd
4th
5th
070 00012 32035 9
* These condensing water heaters require a bracket for the
control board:
RC98HPi (REU-KA3237FFUD)/RC98HPe (REU-KA3237WD)
/RC80HPi (REU-KA2530FFUD)/RC80HPe (REU-KA2530WD)
/REU-KM3237FFUD/REU-KM3237WD/ REU-KM2635FFUD
/REU-KM2635WD
Install the bracket with one screw as shown above and
continue with the rest of the installation.
Install the bracket
Attach the control board
Attach the control board to this bracket with one screw in Step 1.
Ground wire of
Communication Cable A
Ground wire of
Communication Cable A
If multiple MSB-M are used, then at least three water heaters
should be connected to each MSB-M.
Ex: With 7 water heaters, one MSB-M should control 4 water
heaters and the other MSB-M should control 3 water heaters.
On the 2nd to 5th MSB boards, set to 1 unit ready.
