In all probability, it may be an issue with your compressor if you discover that your air conditioner just isn’t working as it should. Some basic troubleshooting can help to determine whether that is the cause, although most homeowners aren’t qualified to do other than essential maintenance and troubleshooting. It will take a professional AC technician to carry out many of the diagnostic tests.

What Is the Compressor?

The compressor is almost certainly located in the outdoor unit if you have a standard residential AC system in your home, and if the compressor isn’t working, your system won’t work. In the compressor, low pressure and cool gaseous refrigerant is compressed until it reaches a higher pressure and a higher temperature and is then squeezed into your unit’s condenser. The process can’t be carried out if the compressor in your air conditioner won’t turn on, for whatever reason.

Check the Power

A tripped breaker or a fuse that’s blown can mean your air conditioner isn’t working as you expect it to. Although it seems obvious, a good first step is simply to check that the power source is getting to your AC unit. Breakers and fuses shouldn’t have frequent problems, and if yours are causing a loss of power more often than they should, an electrician may be needed to diagnose and fix the problem. In general, your air conditioning unit doesn’t respond well to continual stops and starts, especially the compressor.

An HVAC repair services professional may be needed if the breakers and fuses seem to be okay. However, you can check yourself to see if the correct voltage is going into the compressor by using a multimeter if you have one. Fortunately, this issue can be quickly resolved without you having to spend a fortune on it, although you may still need to call an HVAC expert to tackle the problem.

Troubleshooting Steps that Professionals Use

Your HVAC technician is better equipped to tackle the problem if you are able to tell them for sure that it’s a problem with the compressor system. And you may not have to break down and buy a whole new air conditioning unit, although many homeowners fear that’s the case if they have an issue with the compressor. Any of the many parts that make up a compressor may be the source of the problem, and each one will be carefully looked at and considered by the AC technician that comes to your home.


A broken or malfunctioning capacitor is often the culprit if the compressor on your AC unit isn’t working, and the issue can be permanently resolved by switching it for a hard start capacitor. If your compressor won’t turn on, troubleshooting the capacitor is a logical next step, and the only way to do that is by testing the unit after replacing the capacitor.

Start Relay

Again, the only sure way to tell if the start relay is working as it should is to replace it and then test the AC unit. The problem is fixed if a technician installs a new start relay and the compressor then works.


If your compressor isn’t working, it may well be a broken valve causing refrigerant to access the compressor inlet instead of gas. Your air conditioner just won’t cool the air in this scenario, although the compressor may still be running. The problem is typically fixed when you replace any broken valves.

Terminal Connections

You can have some serious issues with your AC unit if the terminal connections are loose or not in place, and it’s an obvious step for your technician to check these. And you may just need to clean the terminal connections if they are dirty; it often is as simple a fix like that.

Dead Compressor

Most homeowners who have air conditioning have two main options to consider if they discover that the compressor in their air conditioner is completely dead and just can’t be fixed, no matter what. If this happens to you, you may decide it’s time to buy an entirely new AC system, or you may decide it’s easier just to replace the compressor. Replacing the compressor will generally cost you under half of the cost of a whole new unit, so clearly, the cost is a factor when making that decision. It may make more sense from an economic point to buy a whole new air conditioner if the cost of buying a new compressor comes to more than 50 percent of the cost of the new unit.