I brought this question to all of our Service Technicians and the consensus amongst all the emergency calls they are called to come assess are…

1.  Air Conditioning water drain lines clogging where a drain safety switch is utilized within the line causing the switch to trip and not allow the compressor to turn on. This, on one hand is a benefit because if indeed the drain line is clogged, water doesn’t build up and leak out all over the floor from the air conditioner.

2.  The second major cause of an Air Conditioning systems to not operate is a De-Humidistat set improperly which is usually located just next to the Thermostat.