There can be several reasons why an air conditioner stops cooling after a while and then starts again when you switch it off and on again. Here are a few possible causes:
Frozen evaporator coil: If the evaporator coil inside the air conditioner becomes frozen due to inadequate airflow or refrigerant issues, it can impede the cooling process. When you turn off the AC, the compressor stops running, allowing the ice to melt. Once you switch it back on, it may cool properly again until the coil freezes over once more.
Dirty air filter: A dirty or clogged air filter can restrict airflow to the evaporator coil, leading to reduced cooling performance. Over time, the restricted airflow can cause the evaporator coil to freeze. When you turn off the AC, the ice melts, temporarily restoring cooling until the coil freezes again. Regularly cleaning or replacing the air filter can help maintain proper airflow.
Overheating components: If the AC unit's components, such as the compressor or condenser, become overheated due to various reasons like electrical issues or blocked airflow, they may shut off as a safety measure. When you switch off the AC and then turn it on again, the components have a chance to cool down and reset, allowing the unit to resume cooling temporarily.
Thermostat issues: Malfunctioning thermostats can cause erratic cooling behavior. If the thermostat fails to accurately detect the room temperature or if there is a calibration issue, it may not signal the AC to cool properly. Restarting the AC can sometimes reset the thermostat and temporarily restore cooling until the issue reoccurs.
Refrigerant problems: Low refrigerant levels due to leaks or other issues can hinder the AC's cooling capacity. When the refrigerant levels drop too low, the cooling performance may diminish or stop altogether. Turning off the AC and then turning it back on may provide a temporary improvement until the refrigerant levels deplete once more.
If you're experiencing this issue with your air conditioner, it's recommended to have it inspected and serviced by a professional HVAC technician. They can diagnose the specific problem and perform any necessary repairs or maintenance to restore the proper cooling functionality of your AC unit.