What Can Cause Your AC Compressor To Overheat?

Your air conditioner's compressor is the hardest working part of your home's air conditioning system. This mechanical component is similar to a pump, but its design means it can only move gases, not liquids. Compressing the refrigerant vapor increases its pressure significantly, requiring your compressor to draw a substantial amount of energy and produce quite a lot of heat.

Like any machine with moving parts, too much heat can cause your compressor to fail by reducing the effectiveness of its internal lubrication, wearing out bearings, and ultimately causing mechanical failure. Your compressor normally relies on ambient air and the condenser fan to keep it cool, but situations can arise that allow it to overheat. 

Spotting the Signs of an Overheating Compressor

Modern air conditioning compressors contain safety switches that allow them to shut down before overheating. As a result, short cycling is the most typical sign of an overheating compressor. Your system may run for a while until the compressor becomes too warm, at which point the safety switch triggers and the system shuts down.

The simplest way to recognize short cycling is to watch your home's thermostat. Your air conditioner should normally run for long enough to reach your setpoint, at which point it will shut off. If your system shuts down before reaching its target temperature, that's a good indication that you have a short cycling problem.

However, not all short cycling problems are due to an overheating compressor. Your system can also short cycle due to a faulty thermostat, restriction in your refrigerant line, refrigerant leak, or any number of other issues. Still, short cycling is always an issue, so it's important to have a qualified technician address the problem as soon as you notice it.

Understanding the Causes of Overheating

If you think your compressor may be overheating, there are a few things you can check. First, make sure the condenser fan on your outdoor unit is operating. This fan should run whenever the compressor turns on and generally operate quietly and smoothly. An unbalanced, damaged, or seized fan will reduce system efficiency and may cause your compressor to overheat.

You'll also want to look for signs of debris, dust, and dirt on the condenser coils. You should hire a professional to clean these coils about once per year. If the condenser coils become too clogged, they can impede airflow to the compressor, causing it to overheat under load. You can try giving your coils a quick cleaning yourself using only water and a low-pressure garden hose.

Remember that your compressor is the most expensive and essential part of your home's air conditioning system. If your compressor is overheating, stop using your system and call in a technician as soon as possible. While the safety switch will protect the compressor for a while, repeatedly causing it to overheat will likely lead to much more expensive problems.

Reach out to an air conditioning repair technician for more information.