How a Split System Air Conditioning Unit Works - The Basics

Residential A/C and Heating Systems in the San Antonio, TX Area

In San Antonio, as a matter of fact, throughout Texas and the whole United States, air conditioning and heating units are the norm in any home or business. In certain parts of the country, one will notice different types of cooling and heating systems used because they are most safe and economical. In Texas, the predominant unit used for home air conditioning is called the split system.

The split system has two parts - the inside unit, which can be an air handler or a furnace, and the outside unit, called a condenser. These two parts of your air system are connected by two copper pipes and a 24 volt control wire which sends electronic signals back and forth between the two units. Both of the copper lines carry refrigerant in different phases. When you look closely, you will notice that one of the copper lines is larger in diameter than the other.

The larger line is called the "suction" line. It has this name because the refrigerant in this line is being "sucked" into the condensing unit by a compressor. The refrigerant in the suction line is in a gaseous or vapor form. The refrigerant is then pulled into the compressor in the condensing unit, where is compressed back to liquid form. When the gas is compressed, the heat it picked up from the inside unit becomes apparent. Next, the hot, compressed refrigerant travels through the condensing coil, which disperses the heat by a fan pushing cooler air through the fins of the coil. That's why you feel hot air coming from your outside air conditioning unit when it's running (in most cases).

The smaller copper line is called the liquid line. When the compressed refrigerant finishes running through the condensing coil, it enters the liquid or low pressure line. The refrigerant from the liquid line travels to the evaporator coil where it picks up heat from the air being pushed through it by the blower. Once the heat has been drawn out of the air, cold air is discharged from the unit to the duct-work and ultimately to the vents. The refrigerant cycle starts over again at that point.