Mars Comfort-Aire Century MCB18 SA Series Installation And Owner's Manual page 12

Wired Controller IOM - VCDxxSA
3. Inst allat ion met hod
The main/secondary wired controller can be used to enable
two wired controllers to control one unit, and the wired
controllers connect to the unit HA and HB ports through the
HA and HB port on the controller. There is no polarity between
HA and HB. SeeFig. 3-8
Indoor Unit
HA HB
0
Wired Controller 1
1
Wired Controller 2
Fig.3-8
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