77
CASCADE
SYSTEM CONNECTIONS
Cascade Communication Bus
Up to four MVB water heaters can be connected in a cascade formation without any external controls.
Designate the primary water heater as the Master water heater / water heater 1 by leaving
dip switch
2
on the VERSA in the UP (ON) position. All other VERSA controls require
dip switch 2
to be toggled
DOWN (OFF), designating them as Followers (Slaves). Refer to
on page 77.
For heater rotation to occur, the Master heater's VERSA control board
dip switch 6
must be set to the
up (ON) position (default is down
– OFF). Rotation is fixed at 48 hours difference between min run time
and max run time i.e. at 48 hours difference, the lead heater becomes the heater with minimum run
time once current CFH is satisfied.
Use standard 1mm wire to connect from the Master VERSA at terminals
A and B
marked
‘PIM FT_Bus
2’
etc, to each corresponding Follower at terminals
J3
marked
‘FT_BUS’
on the PIM™ by pressing
down on the slots with a small screwdriver and then inserting the wires into the holes.
OBSERVE POLARITY between terminals A and B on the PIM and Versa. Refer to
on page 77. A total of 3 Followers can be connected to the VERSA on the Master.
It is recommended that the shortest length cable possible be used to reach between the water heaters.
Do not run unprotected cables across the floor or where they will become wet or damaged. Do not run
communication cables parallel with, or close to or against, low voltage (120/240 volt) wiring. The total
maximum length of each set of communication bus cables should not exceed 60m.
Fig 44: MVB Cascade System Wiring and VERSA DIP Switch Settings
1 2 3 4 5 6 7 8
VERSA MASTER
ON
1 2 3 4 5 6 7 8
VERSA FOLLOWERS
ON
AB
MASTER
DIP 6 ON
FOR
ROTATION
