If a central air conditioning unit is blowing cold air outside and room temperature air inside, it is likely experiencing a problem with its refrigerant system. The refrigerant is the substance responsible for absorbing heat from inside your home and releasing it outside, thus providing cooling. Several issues could be causing this problem:
Refrigerant Leak: A refrigerant leak is one of the most common reasons for this issue. When the refrigerant level is low due to a leak, the AC unit may still be able to cool the air outside (during the evaporator coil's operation) but won't have enough refrigerant to properly cool the air inside.
Restricted Refrigerant Flow: A restriction in the refrigerant lines can limit the flow of refrigerant to the indoor evaporator coil. As a result, the cooling capacity inside your home will be reduced, while the outdoor unit may still be able to expel heat.
Faulty Expansion Valve or Thermostatic Expansion Valve (TXV): The expansion valve is responsible for controlling the flow of refrigerant into the evaporator coil. If it is malfunctioning, it may not allow enough refrigerant to enter the coil, leading to inefficient cooling indoors.
Dirty or Frozen Evaporator Coil: A dirty or frozen evaporator coil can hinder heat absorption, making it less effective in cooling the indoor air.
Compressor Issues: Problems with the compressor, such as a faulty compressor motor or low compressor efficiency, can lead to reduced cooling performance indoors.
Improper Sizing or Installation: If the AC unit is undersized or not installed correctly, it may struggle to cool the indoor air adequately while still expelling heat outside.
Airflow Problems: Issues with the airflow, such as blocked or restricted air ducts, dirty air filters, or malfunctioning blower fans, can affect the cooling efficiency inside your home.
To diagnose and fix the issue, it is best to contact a qualified HVAC technician. They will be able to inspect the central AC unit, identify the specific problem, and perform the necessary repairs or adjustments to restore proper cooling performance both indoors and outdoors. Regular maintenance of your central AC system can also help prevent such issues and ensure its optimal performance.