What To Do When Your Central Air Conditioning Compressor Stops Working


Your air conditioner may not look overly complex but there are several different systems working inside it to produce the ice-cold air you need. One of the best ways of extending the life of your AC unit is to look after it. Of course, that doesn’t mean it will never fail, but it’s less likely and almost certain that your unit will last for years longer than one that hasn’t been looked after. 

Used with permission of Patterson Custom Homes, Brandon Architects and photographer Darlene Halaby

Naturally, when your central air conditioning compressor stops working will be when you need it the most. That’s why it’s a good idea to have it serviced in the winter and know the most common reasons it has stopped working.

Understanding The Function Of The Compressor

Your air conditioner is full of fluid, known as refrigerant. This fluid is capable of removing the warmth from the air around it. The higher the pressure of this refrigerant, the more efficient it is in drawing warm air from the surrounding air.

One fan pushes the now cold air into the house while the other pushes air past the hot refrigerant, allowing the heat to leave the house.

The compressor is critical to this process as it compresses the refrigerant, this increases the pressure of the liquid, turning it into a hot gas which is most efficient at removing heat from the air.

Naturally, if the compressor stops working, the heat can’t be removed and the air conditioner won’t offer the cold air you need.

There are several things that can be wrong with your compressor. Although it is worth taking a look, you should also contact the specialist in industrial air conditioning to ensure your unit is inspected and repaired if possible.

Don’t forget that refrigerant leaks will affect the ability of the unit to function. You should inspect it regularly to ensure there are n leaks and, if there is, get the professionals to fix the leak and refill the refrigerant, if possible.

Dirty Filters

Window with flowers and statues
Used with permission of Breeze Giannasio

This is one of the easiest fixes. When the filters in your AC unit aren’t cleaned or replaced regularly, there will be a build-up of debris. This will reduce the ability of air to flow through the machine, lowering the amount of cold air created.

Unfortunately, this lack of airflow will also place a strain on the compressor and it is likely to overheat. In most cases the unit will shut down, allowing it to cool while you clean the filters. In some cases, the compressor will simply stop working altogether.

In short, keep the filters clean to avoid this issue in the first place.

Starter Relay & Associated Capacitors

Air conditioners have an array of electronics inside them, including capacitors that are designed to accept power from the main supply and transfer it to the compressor, as well as the fans for blowing cold air in and hot air out.

The capacitors develop the power needed but you need to have a starter relay between them and the various parts to ensure they start properly. If these components fail then the air conditioner will no longer work. This is generally the issue when the compressor isn’t doing anything but the unit is humming.

The good news is that these parts can be easily replaced by a professional.

Power Issues

Bedroom with double bed, nightstand and a lamp on it
Used with permission of Breeze Giannasio

If the compressor isn’t working but the rest of the unit seems to be fine, then you may have an electrical issue. You’ll need to trace the wires to locate the ones that aren’t delivering power In many cases this is simply a blown fuse or a loose connection.

If the entire unit is failing to do anything then the power issue is probably with your circuit breaker.

The Compressor Has Died

The compressor can cope with a lot. But, if left to overheat it can be finished for good. Equally, a capacitor going down or some other electrical fault shorts the compressor, it is likely to be damaged beyond repair.

You’ll then be left with two options, replace the compressor or replace the entire unit. The decision regarding which is the better option will depend on the budget you have available and how often the unit is breaking down. The older and more fragile the unit is the more likely it is you’ll have more issues. In this instance, it’s generally better to replace the unit rather than to keep fixing it.

Don’t forget, the best way to reduce the likelihood of these problems arising is to have regular maintenance done by someone that knows what they are doing.

Thanks to all the companies linked above.


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