Refrigerant lines are two copper lines that connect the outdoor air conditioner or heat pump to the indoor evaporator coil.
The larger line typically carries a cool gas and is insulated. This is commonly referred to as the suction line, but it is also called the return line or vapor line.
The smaller uninsulated line typically carries a warm liquid. It is most often called the liquid line.
Learn more about the difference between R-22 and R-410A refrigerants
