What You Should Know About Your Central Air Conditioner's Refrigerant Lines And Their Maintenance

You may have noticed the pair of black pipes that join your central air conditioner's outdoor unit and home and wondered what they do. These pipes contain the "lifeblood" of your central air conditioning system, the refrigerant. If they are damaged or compromised, your system will work poorly and inefficiently, if at all. That is why it is critical for you to take measures to protect them from damage. Below is more information on these refrigerant pipelines and what you should know about their maintenance:

Why refrigerant lines are important to the functioning of your system

While inspecting your outdoor unit, which contains the compressor and condenser, you will observe that one of the lines is wrapped in foam insulation and is larger than the other, smaller, non-insulated line. The large-diameter line is called, variously, a suction line, vapor line, or return line. Its main purpose is to return the low-pressure refrigerant gas to the compressor and condenser for re-pressurization.

The small-diameter line is known as the liquid line or high-side line. This line contains pressurized refrigerant that travels in the form of a liquid to the evaporator. Once refrigerant reaches the evaporator, its pressure drops and allows the transfer of heat from inside the home to the rapidly expanding gas refrigerant. This cycle repeats itself over and over again to provide cooling to your home.

Protect the insulation on the suction line

The suction line is insulated with foam in order to prevent condensation on the line from causing water damage inside your home and to also keep it from needlessly absorbing heat once it leaves the evaporator. The more heat absorbed after it leaves the evaporator, the less efficient the cooling process will be. Note that the smaller liquid line does not need to be insulated and can remain bare.

That is why protecting the insulation on the suction line is so important. If you notice that the suction line insulation is drying, cracking, or deteriorating, then you will need to strip the old remnants away and install new insulation or have a professional perform the job. To keep the insulation in tip-top shape, protect it from being scratched or damaged by shrubbery, and don't allow system condensate to drip continuously on the line. In addition, keep pets and other animals away from the line, as they may chew or urinate on the insulation, thus shortening its lifespan.

Protect the lines themselves

The insulation is not the only thing that needs to be maintained; you will also need to protect the refrigerant lines, too. Made of copper, refrigerant lines are soft and pliable, but this can also permit punctures and breaks. That is why you will need to be cautious to keep the lines from being damaged.

One of the most vulnerable spots for refrigerant-line damage is the space between the outdoor unit and the house. The lines are exposed to the elements and other potential dangers, such as:

Lawnmowers and other landscaping equipment

When mowing or edging around the outdoor unit, you need to be cautious not to make contact with the refrigerant lines. They may be hidden beneath or behind tall grass or weeds, and one nick from a mower blade is enough to penetrate the line and allow for a full release of refrigerant. That is why keeping plant growth under control in the vicinity of refrigerant lines is important and why it may be better to use herbicides instead of power lawn equipment.

Pad movement or house settling

Another common problem with refrigerant lines is damage due to movement of the outdoor unit support base, either due to settling or breaking of the pad, or settling of the house itself. Such movement is often subtle and not easily detected by casual observation; however, if the refrigerant lines are not provided with adequate slack, even small movement can stretch the lines and cause breakage or kinking. That is why you need to inspect your lines to be sure they aren't being pulled taut and that they have plenty of room to "adjust" naturally in the event of pad movement or home settling. If you are concerned about the lines, then contact an air conditioning repair professional to add more length or make adjustments to provide this needed slack.