Why Did Your AC Compressor Fail?
For most split air conditioning systems, your compressor is located outside of your home in the condenser unit. Along with the compressor, this unit contains a blower fan, the condenser coils, and the plumbing and electronics that control the whole system. Although the entire condenser unit is necessary for your system to function properly, the compressor is the most expensive and important part of the unit. The compressor is the pump that allows refrigerant to flow through your system, so a failed compressor will keep your AC system from running at all.
Undersized Compressors Wear Out
If your condenser unit is undersized for the amount of space that it must cool, then it can overheat. Compressors have built-in protection that shuts the system down in the event that they are working too hard, but these shut-offs are intended to prevent damage due to infrequent overheating. If your compressor is constantly shutting down because it is overworked, the extra wear and tear on its internal parts will likely cause it to fail completely. Luckily, professional HVAC installers rarely recommend units that are undersized, so this is not a common cause of failure.
Lack of Refrigerant Can Cause Icing
A system being undersized for the area it is cooling is not the only issue that can cause a compressor to overheat, however. All AC systems are designed to use a specific amount of refrigerant. If there is too much or too little refrigerant in the system, it can cause a variety of issues. Although it can seem counterintuitive, low refrigerant actually causes a greater amount of cooling within the evaporator coils. This usually produces ice on the evaporator coils and it can cause your compressor to overheat and shut down. If the refrigerant itself is cooled enough to remain in a liquid state when it reaches the compressor, then the whole unit may fail.
Poor Internal Lubrication Grinds Compressors to a Halt
Just like a car engine, your AC compressor requires oil to stay lubricated. If there isn't enough oil in the compressor, friction will wear down internal parts and cause enough heat to wreak some serious havoc. Compressor lubrication levels should be checked at least once per year, although problems can easily arise in between inspections. In general, oil pressure may fall due to leaks in the system or as a result of failed pumps. In some cases, the oil may also become contaminated, ruining its ability to lubricate properly. Either way, the compressor is unlikely to survive the experience.
If you notice there is a problem with your AC compressor, contact a local HVAC repair company to determine the best way to fix the problem.