Air Conditioner was running fine, turned it up from 72 to 74 degrees and it started blowing warm air and 1 hr later showed it was 76 degrees in the room. Have been having problems with unit not wanting to kick off or when it kicks off won't come back on. So last week I kicked main breaker and unit came on and has been working since with no problems. Then today after turning the temperature up on the thermostat started having problems again, where it's blowing warm air instead of cool. What can be causing this?? I have talked to several a/c professionals in my area and they don't have a clue other than telling me I need a new unit. This unit heats and cools fine just don't want to kick on or off.