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Air Conditioner Troubleshooting Guide


Get the answers you need to troubleshoot your cooling system from a brand you trust.

Air Conditioner Troubleshooting Tips and Tricks

Your air conditioner works to remove heat and humidity from your home, in order to keep you cool and comfortable inside during the warm weather months. When something prevents your air conditioner from doing this job, it can result in a less comfortable indoor environment for you. This air conditioner troubleshooting guide gives you tips for some quick fixes you might be able to try yourself when something goes wrong with your system, plus advice on when it’s likely time to call in the professionals.

AC is not turning on

There are a few different things that might cause your air conditioner to be stuck on the off setting. Some possible causes, like dead batteries in your thermostat or a clogged filter, can be quickly and easily mitigated. Other issues, like a clogged AC drain line, or even a motor failure, require more serious troubleshooting that likely needs to be handled by a professional.

What can I do?

If your air conditioner isn’t turning on, your first step should be to check your thermostat. Your thermostat controls your air conditioner; sending messages to your system that it’s time to turn on, turn off, speed up, or slow down. Therefore, your air conditioner might not be turning on because your thermostat has dead batteries, and all you’ll need to do to get your system up and running is change the thermostat batteries. If your thermostat appears to be working, try checking the filter within your HVAC system. An extremely dirty air filter might result in your AC “freezing up” from lack of airflow across the indoor coil, but luckily, homeowners can change air filters regularly themselves to alleviate the problem. However, if you do not feel comfortable changing your air filter, you can always call an HVAC technician to help.

If neither of these measures appear to solve the problem, your air conditioner likely requires more advanced troubleshooting and maintenance. In this case, contact your local HVAC dealer to help determine the problem and advise if you’ll need to repair or replace the system.

AC not blowing cold air

Similar to if your air conditioner is not turning on, there can be many causes of your AC not blowing cold air. While you can attempt some thermostat troubleshooting to mitigate this issue, most root causes here, like a broken AC compressor or leaking refrigerant, should be handled by an HVAC professional.

What can I do?

Check your thermostat to ensure it’s set to the correct temperature. You might not have realized your thermostat is set higher than your desired temperature, which could result in you feeling particularly warm indoors. Try lowering the temperature, then wait an hour to see if you notice any difference. Additionally, homeowners can also check outdoor unit operation. To do this, without touching your outdoor unit, hover your hand over the top of it and see if you feel hot air coming out of the unit. If you don’t or if you still feel too hot in your home, the problem is likely something bigger, like a malfunctioning AC compressor.

Your air conditioner compressor is a vital part of your system, responsible for cooling, circulating, and compressing the refrigerant that cools the air in your home. But because it’s located outside the home, it can also be outside our frame of mind when things go wrong. But, an HVAC professional will be able to inspect the compressor and determine if it’s the cause of your AC issue. Alternatively the problem might not be with the compressor, but could be with a refrigerant leak inside. Refrigerant is a dangerous chemical cooling component that should only be handled by a professional.

AC is continuously running/won’t turn off

An air conditioner that is continuously running and won’t turn off is likely caused by a faulty thermostat or an incorrectly sized system. If your thermostat isn’t sending the correct messages to your air conditioner, your AC might never turn off. The problem could also be caused by a system that isn’t equipped to cool a certain home size. It’s also important to note that external factors unrelated to your HVAC system’s functioning might be causing it to continuously run, like unusually high temperatures for prolonged periods.

What can I do?

Try the typical thermostat troubleshooting steps like changing the batteries and adjusting the temperature. If none of those alleviate the problem, your AC continuously running could be because you don’t have the correct size system for your home. An AC that is too small runs constantly and never hits the set point, while an AC that is too large can constantly alternate between on and off. The appropriate size AC will help ensure energy efficiency and consistent comfort. Start researching the size and type of AC system for your home, then contact an HVAC professional who can do a load calculation and work with you to find the perfect system for your home.

AC troubleshooting: Signs it’s time for a replacement

While some air conditioner issues are DIY fixes, and others are quick repairs that can be done by an HVAC professional, other issues mean it’s time for a new system. If your air conditioner meets any of these criteria, it might be time to replace your system altogether:

  • Your air conditioner is over 20 years old. 
  • Your air conditioner frequently needs repairs.
  • Your air conditioner regularly produces strange noises and smells. 
  • You’ve noticed recent, inexplicably high energy bills.

Help prevent air conditioner issues

While some problems with your air conditioner are inevitable and a result of the system age, your home size, and a number of other factors, there are some things you can do to help prevent potential issues. Regular AC maintenance, like changing your air filters and keeping the area around your system free of debris, can help problems from occurring.

Additionally, remember to schedule maintenance with a professional twice a year. An HVAC professional will be able to diagnose problems early, before they become catastrophic, and advise you on the best next steps when there is an issue. Contact your local American Standard Customer Care Dealer today to discuss AC maintenance and any troubleshooting concerns.

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