There can be a few reasons why an air conditioner unit continues to run even when it's not cooling and the thermostat is turned down or off:
Incorrect thermostat settings: Double-check the thermostat settings to ensure it is set to the desired temperature and cooling mode. Sometimes, the thermostat may be set to "fan only" mode, which will continue to run the fan without cooling.
Thermostat malfunction: The thermostat could be malfunctioning and not accurately sensing the temperature, causing the AC unit to run continuously. Consider replacing or recalibrating the thermostat if you suspect it is faulty.
Airflow issues: Insufficient airflow due to blocked vents, dirty air filters, or obstructed ducts can cause the AC unit to run longer to achieve the desired cooling. Check the vents and filters to ensure they are clean and unobstructed.
Refrigerant leak or low refrigerant levels: If the AC unit has a refrigerant leak or low refrigerant levels, it may struggle to cool effectively. As a result, the system may continue to run in an attempt to reach the desired temperature. A professional technician should be called to inspect and address any refrigerant-related issues.
Compressor or mechanical problems: Faulty components within the AC unit, such as a malfunctioning compressor or motor, can prevent the unit from cooling properly. This can lead to the AC running continuously. A qualified technician should be consulted to diagnose and repair any mechanical problems.
If you are experiencing persistent issues with your air conditioner running unnecessarily, it is recommended to contact a licensed HVAC technician to diagnose the problem and provide appropriate solutions.