An air conditioner compressor is one of the most essential parts of your unit as it is responsible for circulating the coolant around your air conditioning unit, allowing the refrigerant to cool the air. When the compressor overheats or malfunctions, your cooling system can no longer function properly.

Causes of AC Compressor Overheating

Cause #1: Damaged or Dirty Air Filter

Damaged or dirty air filters restrict the airflow around the unit, causing the warm air to get trapped inside. The air conditioner would have trouble getting air through a dirty or damaged air filter as well, which forces the unit to work harder. These can cause the compressor to overheat as it works harder to circulate refrigerant with the restricted airflow.

Cause #2: High Head Pressure

Similarly, dirty condenser coils in the air conditioner's outside unit may get clogged as dirt and debris pile up through the vents. Dirty coils cause high head pressure, which may make your compressor overheat as the cooling system fails to let the warm air out of the unit.

Alternatively, high head pressure can also be caused by a nearby heat pump, which warms the unit resulting in overheated compressors. Ambient temperature during extremely hot summer months can also contribute to overheating. However, the most common reason for high pressure is a dirty coil.

Cause #3: Low Refrigerant Levels

When there's not enough coolant for the compressor to circulate, it can start to grind the AC system, which causes the mechanisms to overheat. Low refrigerant levels usually lead to serious problems, like leaking water, frozen AC coils, and even burnt smells. That burnt smell is the compressor overheating.

Low refrigerant charge is often caused by a leak in the refrigerant pipes. In this case, it is best to contact one of our Luce Aircon technicians to find the leak and repair it. The technician would add a neon dye to the refrigerant to follow the path to the leak, and repair the leak immediately before it damages your unit further.

Cause #4: Inadequate Air Conditioner Size

Not all air conditioning units are the same, and the main difference with various models is the efficiency in their cooling capacity. The general rule is that the larger the area you need to cool, the stronger the air conditioning system is required to properly cool the space.

An air conditioner that is too small or weak to cool the room to the desired temperature will force the system to work harder to achieve the temperature set on the thermostat. This causes an overheating compressor.

Cause #5: High Voltage Surge

A surge of high voltage may be rare in your area, but it is a probable cause of an overheating compressor. The high voltage may cause your cooling system to trip a circuit, and may also cause the compressor to overheat. You may notice a burning or exhaust smell coming from your unit when this happens, where you should unplug your unit immediately for your own safety.

Troubleshooting Guide

Fix #1: Clean the Air Filters and Evaporator Coil

One of the most basic care routines you can do at home for your air conditioner is to clean the air filter and the coils. You can easily clean the filter using some soap and water, and a vacuum cleaner can remove the debris from the inner layers of the coils. You should be cleaning your filters at least once every two weeks.

Fix #2: Clean the Condenser Coils, and Remove Heat Source

Remove any heat pumps or heat lamps nearby your unit, and provide sufficient insulation to protect your unit from extreme sunlight and high temperatures. Clean the condenser coils with a jet spray of water, and use a soft-bristled brush to scrub the dirt out while the unit is turned off and unplugged.

Fix #3: Top Up Coolant

Contact a technician to find and fix the leak, and have your refrigerant levels topped up as needed. Monitor your refrigerant levels to schedule a top up before your AC unit has problems with the refrigerant lines.

Fix #4: Match Aircon Size to the Room

At Luce Aircon, we offer purchasing and installation services that would guide you to a suitable unit and area for you to adequately cool your room. Skip the guesswork, and find an appropriate model for your space, and our experienced technicians are there to assist you in making your purchase.

Fix #5: Contact a Luce Aircon Technician

For any electrical problem, or issues with the internal parts of your air conditioner, you contact us to learn more. With decades of combined experience in cleaning, maintaining, diagnosing, and repairing air conditioners across Singapore, our HVAC professionals are sure to find the root of the cause of your AC unit, and keep the unit in tip top condition!

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Check out our article on ac compressor not working but fan is running!