The Blower Fan Won't Turn Off on My Trane 1200XL Air Conditioner

Outdoor Temperatures

• If you were not advised on the correct size of air conditioner to install in your home, the problem may be because the system is simply too small for your needs. The air conditioner may need to work overtime to reach the desired temperatures. Even if the system is properly sized for your home, extreme heat outdoors could cause the air conditioner to remain on and blow all the time to try to cool your home. This issue could be the result of the weather, a lack of insulation in your home or an undersized air conditioner.

Thermostat Settings

• Your blower can be set to stay on constantly even when chilled air is not being produced. Some prefer to set the fan switch to the “on” setting to help the circulating air even out the temperatures throughout the home. It is not absolutely necessary, and turning the switch to the automatic setting will mean it only blows when it is actually cooling. Check your fan switch to see if it is “on,” and then switch it off or to “auto” to stop the constant airflow. You may also have your temperature set too low on the thermostat, meaning the air conditioner is constantly trying to make the home unreasonably cold. Try raising it a few degrees to stop the blower.

Clogged Air Filter

• The removable air filter at the indoor intakes near the blower must be changed regularly for optimum efficiency. These filters screen out dust and debris that can negatively affect your air conditioner. If the filter is allowed to get so dirty that it begins to clog, the airflow to the blower will be restricted and the air conditioner may not be able to cool the house to the desired temperature. This may result in overheating and is likely to make the system stay on all the time in severe cases.

Outdoor Coil Debris

• Check your outdoor unit. This is where the evaporator coil is located and where the chilled air is produced. If debris such as lawn clippings or other objects are blocking the airflow to the outside unit and the cooling coil, the air will not be cold enough coming through the ductwork, and the house will not be able to reach its goal temperature. Therefore, the air conditioner will remain on as it tries to do its job without success.