If your central air conditioner stops cooling but still blows cold air when turned on after being off for several hours or overnight, it could be due to a few possible reasons:
Thermostat Issues: The thermostat may not be functioning correctly. If the thermostat is not accurately sensing the temperature or is not communicating the cooling demand properly to the air conditioner, it can cause erratic behavior like this.
Frozen Evaporator Coil: The evaporator coil inside the indoor unit of the air conditioner can freeze if there is restricted airflow or low refrigerant levels. When the unit is turned off for several hours or overnight, the ice on the coil may thaw, allowing it to blow cold air initially. However, as it starts cooling again, the coil can freeze up once more, causing the cooling to stop.
Clogged Air Filter: A dirty or clogged air filter can restrict airflow, leading to reduced cooling efficiency and even freezing of the evaporator coil.
Refrigerant Leaks: Low refrigerant levels due to leaks can result in insufficient cooling. When the unit is turned off for a while, the refrigerant pressure may equalize, allowing it to blow cold air briefly before the cooling capacity diminishes again.
Faulty Compressor: The compressor is a crucial component responsible for pumping refrigerant through the system. If it is malfunctioning, it may not be able to maintain the necessary pressure to provide consistent cooling.
Electrical Issues: Electrical problems like faulty capacitors, relays, or wiring can affect the proper functioning of the air conditioner, causing intermittent cooling.
Air Duct Issues: Problems with the ductwork, such as leaks or blockages, can lead to inconsistent cooling performance.
To resolve this issue, it's best to contact a professional HVAC technician to diagnose and repair the problem. They can perform a thorough inspection, identify the root cause, and undertake the necessary repairs to restore your central air conditioner's proper cooling functionality. Regular maintenance of your HVAC system, including cleaning filters, checking refrigerant levels, and inspecting the overall system, can also help prevent such issues from occurring.