8-30-24 Office AC systems #3 is not working and the thermostat is change your heat to cool by its self. We change the thermostat. The existing one was pretty old. Start up the 10 ton AC system ,when we checked the outdoor unit condenser found a the contactors were chattering they were getting 19 VAC The transformer may be the issue however this is a real long wiring run.I did get a voltage drop across both of my compressor time delays. I bypass the time delays for now and the time delay is in the in the thermostat 3 mins. Cycled system multiple times system is working at this time.Billy will keep an eye on it