Understanding Air Conditioner Refrigerant Lines

Posted on: 26 April 2017

An air conditioning system relies on the coordination of a large number of different components in order to successfully cool the air in your home. While many people recognize the importance of the compressor, the condenser and the evaporator coil, fewer understand the vital role played by the relatively humble refrigerant lines. If you would like to improve your knowledge of home air conditioning installation, read on. This article will discuss the function of the refrigerant lines, as well as commonly experienced problems.


The principal function of the refrigerant lines is--you guessed it--transporting refrigerant to and from the different components of your system. This is an especially important role when considering that movement and circulation is at the heart of an air conditioner's system. In order for cooling to occur, gaseous refrigerant must be constantly shuttled from the evaporator coil to the compressor/condenser and then, once having been condensed to a liquid state, back to the evaporator coil again.

Because the condenser is generally located outside the home, while the evaporator coil can usually be found inside, significant lengths of refrigerant lines are required. These lines are typically made of copper. The lines that lead from the compressor to the evaporator coil have a very thin diameter. These lines are responsible for carrying liquid refrigerant. As this refrigerant enters the wider evaporator coil, it expands into a gas, absorbing excess heat in the process.

This gaseous refrigerant is then routed back to the compressor/condenser in a wider supply line. This line is also responsible for carrying oil from the evaporator coil to the condensing unit. Such oil ensures smooth functioning of the condenser. In order to facilitate its flow, the refrigerant line leading back to the condensing unit is generally sloped downward.


As you can probably imagine, leaks represent the single most significant threat to a refrigerant line. Even a tiny hole will allow refrigerant to escape from the system. This will gradually diminish the overall efficiency of the air conditioner. Because refrigerant lines are often buried in the walls of houses and other hard-to-reach places, it can be difficult to diagnose leaks. The fact that escaping refrigerant quickly evaporates into the air only makes the task harder.

Fortunately, it is often possible to diagnose refrigerant line leaks by the presence of oil stains. Such stains are caused by the oil that also travels through the refrigerant lines. If no oil stains are present, but an air conditioning technician suspects that the system may be experiencing a leak, they will likely employ a more advanced diagnostic tool. These include such things as leak detection fluids, electronic leak detectors, and halide torches.