daisychain citi multi

[cavalieri85]

ok so mitsubishi says we must daisy chain there units my ? is why.

[Thermatech]

The City Multi has what they call Mnet communication system
every indoor unit must have a unique address 01 up to 50.
All indoor units need to communicate data to the BC box & outdoor unit.
So they must all be connected to the outdoor unit & BC box with Mnet communication cable.
The Mnet communication is 30v dc & each indoor unit continually update onto the Mnet its operating data like LEV valve opening, coil temperatures, Super-heat or Sub-cool value, return air temperature & set temperature.
The outdoor unit has constantly updated data from all indoor units & can adjust compressor speed, fan speed & combination of outdoor coils to constantly optamize operation for minimum power consumption.
Each indoor unit can communicate its requirments to the BC box so that the BC box can open the correct port valve to supply hot gas to the units which require heating & suction valve for cooling.

The easiest way to make sure all units are connected with the Mnet communication cable is to run a daisy chain linking all units back to the BC box & then back to the outdoor unit.

Remember that the communication data can be corrupted by magnetic fields around power cables.
So make a gap of atleast 300mm between power cables & Mnet control cable.
Also make sure to use screened cable & make sure you tag the screen part of the cable down to ground in one place & then use the S terminal to daisy chain the screen part of the cable
to all units. This will protect the communication from outside interferance.