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My Air Conditioner Keeps Running When Turned Off! Here’s the Fix

Having your air conditioner continue to run after you’ve turned it off is an issue that you’ll more than likely be able to resolve by utilizing the information here. The cause of this problem can be the result of a number of possible issues, including extreme temperatures, a broken thermostat, a faulty relay switch, or even a short circuit.

The first thing you need to realize is that it’s perfectly normal for your HVAC system fan to continue to run for a few minutes after the air conditioner stops. However, if the fan runs by itself for more than a couple of minutes, then you know there’s an issue. There’s no reason why the fan should run for hours on end. A fan that runs continuously typically means there’s a bigger issue.

Before we begin, it’s important to have a good understanding of the air conditioning system. The blower fan in your air conditioner is a separate electrical system from the cooling unit. However, they work together as a team. As the air conditioning system cools down, the blower fan pulls the warm air from inside of your home, runs it through the air conditioning system, and then blows the now cool air back out into your home.

When you select ‘auto’ on your home’s thermostat, which is the usual setting that you’ll use, both the blower fan and the cooling system will turn off at the same time once the temperature you chose is reached.

Remember, the blower fan might run a few more minutes after the cooling system has turned off. It’s important to note that if you have your thermostat selected to the ‘on’ option, then your blower fan will run continuously. This feature is to provide increased circulation in your home. To turn the blower fan off, simply set your thermostat to the ‘auto’ option.

Air conditioner is turned off but fan keeps running

If your blower fan is continuing to run after the system has already turned off, and you made sure your thermostat isn’t set to the ‘on’ position, then you’ll want to try and pinpoint the issue. Listed below are the three most common reasons why the blower fan continues to run after the system has already turned off.

  1. If it’s extremely hot outside, your blower fan may continue to run. Why? The system just can’t get to the temperature that you set the thermostat to. This is a common problem for homes with an undersized cooling system. In this situation, you can either invest in a bigger and more powerful cooling system, or you can wait until the weather gets cooler. Either way, make sure you perform regular maintenance on your air conditioning system. Failure to properly clean and maintain your air conditioning system can cause it to work harder than it needs to.
  2. A damaged thermostat may also be the issue. If you notice your air conditioner and the blower fan all of a sudden start running, then the problem is more than likely the thermostat. This is fairly inexpensive to fix and installing a new one isn’t that difficult either.
  3. A short circuit or a damaged relay switch will definitely cause you to have problems. Usually, when the relay switch is broken, the fan will continue to run by itself. This happens because there’s no communication between the thermostat and the blower fan. Now, if it’s a short circuit, both the ‘on’ and ‘off’ commands you enter typically won’t get sent to the blower fan. As a result, the blower fan will continue to run. In either of these situations, it’s best to call a local HVAC company to come out and fix the issue.

The benefits of fan maintenance

To ensure that your air conditioner continues to work well, even during extremely hot days, it’s essential to have your system maintained at least once a year. This includes things like:

  • Cleaning the filters and replacing them if need be
  • Checking the refrigerant level and recharging it if necessary
  • Checking the belt in addition to the belt tensioner
  • Lubricating all the necessary parts
  • Fully cleaning the thermostat

Most HVAC companies will do all these things for you. However, if you want to save some money, change the filters yourself. In fact, to keep your system running extremely well, it’s recommended that you change the filters every three months. By doing this, you’ll keep your system running well while you also improve your home’s indoor air quality.

Michael Joseph