What Causes an AC Compressor to Fail
TechXpert verified by Ken Kontra
Dirt and blockages in your system, an incorrect amount of refrigerant, and electrical problems are the main causes of AC compressor failure. Your compressor malfunctions when there isn't enough refrigerant or when it can’t move refrigerant through your system, causing the compressor to fail and leaving you without cold air.
The Heart of Your System
Like your heart pumps blood, a compressor is responsible for pumping refrigerant through your system.
Incorrect Refrigerant Levels
Your refrigerant shouldn’t take the high road — any imbalance in refrigerant level can cause your compressor to malfunction. When the refrigerant level in your AC system is too high, your compressor must work harder. An overcharged system causes the compressor to use more electricity, generating excessive heat within the compressor, leading to damage and poor function.
On the other hand, if your refrigerant levels are too low, your compressor runs constantly to get the same job done. This wears out your system and will cause your compressor to fail over time.
Evaporator (indoor) and condenser (outdoor) coils in your system are prone to dust buildup, and when debris collects, it prevents your compressor from transferring heat efficiently. This means your compressor has to run more often to keep your home cool, and it has to work harder, too. Extra stress on your compressor will eventually cause it to overheat and fail.
Your compressor is the heart of your system, and your air conditioner’s refrigerant lines are like its veins. Just like blood clots, your lines are prone to blockages, and when there’s a blockage, the flow of refrigerant is reduced.
As an electrical component, your HVAC compressor can break down or malfunction because of an electrical failure. In addition to transferring heat out of your home, refrigerant vapor also cools the compressor’s internal motor. When a compressor motor failure occurs it can create acid within the refrigerant, commonly referred to as a “burnout.” An HVAC technician can check if electrical failure is the source of your compressor problems and recommend performing an acid test. Any time there is an internal electrical failure of the compressor, the acid test is necessary to properly diagnose and repair this issue. This acid and contaminants must be dealt with by following strict procedures, otherwise the acid will continue to cause more part failures.
Time to Call a Contractor
Whatever the source of your compressor problem, it’s not an easy fix and should be handled by an HVAC technician, because AC compressor replacement is not a DIY job. If you’re experiencing issues with your compressor it’s time to call in a contractor.
FREE Virtual Home Repair
We'll diagnose your issue over call or video and virtually walk you through the repair — all for free if you're a new customer! .