Industrial AC ? Most units will have their own 12v power supply. There will be 2 pins that if connected will turn on the unit. Use a double strand wire. Run from the 2 pins to your stat. The stat connects the 2 wires to turn on.
Got it figured out. Had to reconfigure the settings on the heat pump to electric heat pump no back up.
It's two 42000 units. One on each side of the house. One was acting up cause the drain line was clogged and the switch was getting triggered.
