If your air conditioner (AC) stops blowing cold air but continues to run for hours before going out completely, there could be several potential issues causing this problem. Here are some common reasons:
Refrigerant Leak: One of the most common causes of an AC not blowing cold air is a refrigerant leak. Refrigerant is the substance responsible for absorbing heat from the indoor air and cooling it. If there's a leak, the refrigerant level drops, and the AC's cooling capacity diminishes over time until it stops working completely.
Frozen Evaporator Coil: If the evaporator coil inside the indoor unit gets too cold, it can freeze, leading to reduced airflow and eventually causing the AC to stop blowing cold air. Several factors can cause a frozen coil, such as a clogged air filter, restricted airflow, or a faulty blower motor.
Dirty or Clogged Air Filter: A dirty or clogged air filter restricts the airflow to the evaporator coil, reducing its efficiency and cooling performance. Over time, this can cause the AC to stop blowing cold air.
Faulty Condenser Unit: The condenser unit is responsible for releasing heat from the refrigerant into the outside air. If it's not working correctly due to issues like a faulty compressor, damaged condenser coils, or a malfunctioning fan, the AC won't be able to cool the indoor air effectively.
Thermostat Issues: A faulty thermostat may not accurately sense the indoor temperature or may not signal the AC to cool properly, leading to irregular cooling or no cooling at all.
Electrical Problems: Electrical issues such as damaged wiring, a blown capacitor, or a malfunctioning control board can cause the AC to behave erratically and may lead to cooling problems.
Overworked Unit: In some cases, the AC may continue to run without blowing cold air if it's too small for the cooling load of the space. Over time, the constant operation can strain the system and lead to a complete shutdown.
To diagnose and fix the issue, it's best to contact a qualified HVAC technician. They can inspect the system, identify the root cause of the problem, and perform the necessary repairs or maintenance to get your AC running efficiently again. Regular maintenance, such as cleaning the filters and coils, can also help prevent many of these issues and keep your AC in good working condition.