Most air conditioning units usually have built-in mechanisms that automatically shut off the system if the desired temperature is already met. Whenever there are problems that allow the A/C unit to continue operating without turning off, its owner must have the air conditioning unit checked. Usually, at least one of the three components have problems if this situation happens.
The Thermostat is Broken
The thermostat sets the temperature the A/C need to cool the room. If the desired temperature is reached, the thermostat sends signals to the rest of A/C to automatically shut off the system. An air conditioning unit with a broken thermostat may continue cooling the room or house beyond the set temperature. Repairing or replacing the thermostat may fix the unit.