One reason a Carrier air conditioner might overheat is that the compressor itself may be short on refrigerant. The principle is the same in all types of units. When the compressor does not have enough of the liquid refrigerant to turn into a cooling vapor, it causes the system to work harder than normal and can lead to overheating. The only way to fix this problem is to have a qualified professional add the necessary refrigerant.
A short circuit can also cause some Carrier air conditioner models to overheat. In 2001, there was a recall on split ductless Carrier air conditioning models sold in Puerto Rico. The short circuit led to a number of reports of overheated air conditioning units that eventually caught on fire due to the excessive heat.
On occasion, a Carrier air conditioner will have a capacitor go bad from too much voltage overloading the system. The amperage can also have an effect on the internal mechanisms of the system. In Carrier models, an internal heat switch will turn off the motor when it gets too hot and overheats. The system needs to be running at optimum capacity to avoid overheating.
One of the more common causes that Carrier and other air conditioning models overheat is related to routine system maintenance. An air conditioner that has to work overtime drawing air through dirty filters will overheat if it is forced to do so continually. Furthermore, the outside coils must also be kept clean to avoid overheating. This can be accomplished with a simple water hose and a pressure spray nozzle.