Mars Comfort-Aire Century VCD24 SA Series Installation And Owner's Manual page 13

Wired Controller IOM - VCDxxSA
3. Installation method
For some units, one wired controller can support multiple units
(a maximum of 16 units). In this case, the wired controller and
unit need to be connected to the HA and HB ports at the same
time. In group control, there will be no error displayed on the
wired controller . SeeFig. 3-9
Wired Controller 1
Indoor Unit 1
HA HB
0
Fig.3-9
Indoor Unit 2
HA HB
1
Indoor Unit n
(n<=16)
HA HB
2
.....
10