Troubleshooting AC Compressor Problems

Published on: May 22, 2013

Air conditioner problems often originate in the compressor. While other issues can go wrong, AC compressor problems are quite common. They are much more likely to occur when routine maintenance isn’t performed on an air conditioning system. The majority of air conditioner compressor issues require professional intervention. However, having a basic understanding of common compressor issues is very useful. By knowing the basics, you can provide more accurate and helpful information to HVAC technicians, and your repair should go a lot more smoothly. In some cases, it may even turn out that the problem is being caused by something simple, and you may be able to avoid a service call altogether.

Common AC Compressor Problems

If the cause of your air conditioning problem isn’t immediately apparent, it’s reasonable to start troubleshooting the issue by taking a look at the compressor. AC compressor problems can trigger various symptoms. A few of the most common include:

  • Unit Turns On and Off Frequently – HVAC technicians refer to this as “hard starting,” and it is problematic for a number of reasons. Every time the compressor kicks on, significant amounts of energy are used. When air conditioners constantly cycle on and off, their ability to achieve and maintain comfortable temperatures is greatly reduced. This issue also hampers an air conditioner’s ability to remove humidity from the air. Hard starting is often caused by blown fuses, but it may also be triggered by electrical problems in the compressor. Something as simple as a frayed wire may be to blame. For safety’s sake, leave electrical issues to the professionals.
  • Reduced Cooling Capacity – An improper refrigerant charge is often to blame for reduced cooling capacity, but it may also be caused by pressurization issues in the compressor itself. If the suction pressure is too high or the discharge pressure is too low, the unit will be unable to maintain the optimal pressure. In turn, its ability to adequately cool your home will be greatly diminished.
  • Motor won’t Start – If the motor in the compressor won’t start at all, a faulty start capacitor is almost certainly to blame. Some units don’t have start capacitors at all, and solving this problem is as simple as having one installed. If your unit already has one, it may be failing or may have failed completely. In that case, replacing it may do the trick.
  • Compressor won’t Start or Keeps Failing – This issue is also usually caused by a defective motor. What usually happens is that the insulation that protects the windings gets worn away. It doesn’t take long after that for the motor to burn out and quit working. A burned out motor can be a costly proposition. With any luck, a fuse will trip to keep it from working once a problem develops. This will actually protect the motor, and the repair will be less involved and less expensive. Unfortunately, compressors sometimes won’t start because they are locked up and beyond repair. They tend to be the most expensive air conditioning components, so this can spell disaster for an AC system. Unless the compressor is still under warranty, it may be time to invest in a whole new system.
  • Compressor Overheats – A variety of problems can cause an air conditioner compressor to overheat. Faulty wiring may be to blame, or the motor may again be the culprit. When it comes to troubleshooting AC compressor issues, you can see that most of them need to be diagnosed and repaired by experienced HVAC technicians.

Ruling Out Simple Problems

One of the best steps to take when troubleshooting AC compressor issues is to keep it simple. It’s easy to overlook very basic problems and have professionals intervene when they’re not really needed.

First and foremost, make sure that power is actually going to the air conditioner. A tripped breaker or blown fuse could prevent that from happening. In the case of a tripped breaker, you can be up and running again on your own in no time.

Even if power is going to the air conditioner, it may not be making it to the compressor. If you have a multimeter, you can check yourself. Otherwise, you will have to wait until a technician can come out to check for you.

Should You Repair or Replace Your Air Conditioner?

As long as the compressor is still under warranty, you should be able to have it repaired or even replaced without a lot of fanfare. If it’s no longer covered by a warranty of any kind and can’t be repaired, however, you may want to invest in a new air conditioning system entirely. It’s not fun to fork over all of that money, but advances in energy efficiency will result in lower bills, and you should be able to recoup your investment before too long. AC Southeast® dealers can help you make the most informed decision possible and provide information regarding rebates and tax incentives as well.