When connecting more then a single refrigerant system, there are couple of conditions that needs to be fulfilled.
1. Wiring should be as below.
2. There are setting on the Mitsubishi Electric outdoor/outdoors units that need to be maintained.
a. The addressing of the indoors and outdoors should be maid in such a way it support multi system connectivity into one control network (it should be part of the HAVC commissioning process)
b. Outdoor - Outdoor communication line (TB7) should be properly configured.
1. It needs to be "powered", meaning, it should be set to provide 32v DC. This is done by moving
CN41 jumper to position CN40 at one of the Master outdoors.
2. In some cases, outdoor - outdoor communication line needs to be "notified" that there is "central control". This is done by moving dip switch SW5-1 to ON.
* Generally, all those settings are required when any type of original Mitsubishi Electric Central control equipment is being used.