Skip to main content

Refrigerant, Copper Lines and Filter Driers

December 30, 2019

Quicklinks to other articles in this series:

What Are Refrigerants, Copper Pipes, and Filter Driers?

Refrigerants, copper pipes and filter driers

Refrigerant is the liquid chemical blend that soaks up heat and releases it as part of the air conditioning process; it is the lifeblood of the air conditioner. Copper pipes act as refrigerant lines to transport this vital fluid throughout the air conditioning system. The filter drier provides physical filtration and absorbs water and other contaminants that can be found in the refrigerant.

Where Is the Refrigerant & Filter Dryer?

Refrigerant runs throughout the air conditioner, from the evaporator coil to the condenser and back again, creating the basic flow necessary for cooling to occur. A technician can maintain refrigerant levels by access ports found on the outdoor unit.

The two main lines of copper piping run from the condenser to the evaporator coil and back. The larger is called the suction (or return, or vapor) line and the smaller one is the liquid line.

You will find the filter drier on the liquid line outside near the condenser or inside near the evaporator coil. It looks like a blue or grey soda can.

The Science Behind Refrigerant

Refrigerant Gauge Up Close

Refrigerant is contained within copper coils inside an air conditioner. As the hot liquid refrigerant is pumped into your home to the indoor coil it is metered by the TXV which only allows a small amount to enter the coil. This creates a drop in temperature of the refrigerant allowing the heat from your home to soak up like a sponge and transfers into the refrigerant to be taken outside as a gas back to the compressor. Finally, once your thermostat senses that enough heat has been removed, it shuts off the system at just the right temperature.

Larger refrigerant lines that carry cold gas need to be insulated. For example; on a warm summer day condensation would form, like the outside of a glass of ice water. In contrast, the liquid line needs no insulation because it contains warm refrigerant.

Filter driers remove moisture from refrigerants. To acheive this, dryers use desiccants, such as activated alumina or silica. Some use molecular sieves, which trap moisture on a molecular level. Also, to keep out common contaminants, filter driers use screens and depth filters, such as bonded desiccant cores or fiberglass pad filters.

What Makes Them Important?

Refrigerants need to have low freezing and boiling points, a low condensing pressure, a high vaporization heat, high vapor density, and a high critical temperature. Moreover, they should be non-corrosive, non-flammable, and non-toxic. For those reasons, refrigerants are carefully synthesized chemicals.

The filter drier’s essential role is to remove water from the system. Water can cause freeze-ups and corrosion from organic acid compounds, so moisture must be eliminated.

As far as materials go, copper tubing is economical and eco-friendly since it is strong, light-weight, and relatively inexpensive. In addition, refrigerants are contained in copper tubing because the copper is efficient at transferring heat.

Different Types of Refrigerants, Copper Pipes, and Filter Driers

R410A Refrigerant Jug

Refrigerants come in two types: the older version, R-22, commonly known as Freon; and R410A, known by its brand name, Puron. For many years the main refrigerant in air conditioning systems was R-22, but due to its effect on the ozone, it was severely restricted from production and will be banned entirely by 2020. R410A is the industry standard now. This is because it is efficient and less harmful for the environment, while providing the same cooling as R-22.

The two main types of copper pipes are hard-drawn copper and soft copper. Hard-drawn copper is very rigid and straight. Soft copper is flexible and comes in 25- or 50-foot rolls. There are markings that indicate that the pipes have been cleaned and dehydrated for use in air conditioning and refrigeration systems.

Filter driers come in various forms, including spun copper, steel liquid-line, steel suction-line, and steel bi-flow. Steel driers provide added filtration and water capacity over copper driers.

Maintenance and Repairs

Be aware that R-22 and R410A are not interchangeable. Your air conditioning system will use only one of these refrigerants. Newer air conditioners will use R410A as its refrigerant. A trained technician should handle refrigerant replacement because these coolants can be dangerous to handle and must be disposed in specific ways.

If you notice oil stains around your air conditioner, you might have a leak, potentially caused by damaged copper pipes. Harsh weather, internal contaminants, or installation in high traffic areas can damage copper pipes. Therefore never reuse old copper refrigerant lines when repairing or upgrading your air conditioner.

And finally, filter cores and drier shells may need to be replaced over time, but thankfully, the market provides a wide range of replacements. Often, these replacement cores and shells are a simple installation for a professional technician.

About The Author

Bob Jenson

For over 45 years, Bob Jenson has been providing quality heating and air services to the San Diego community.

Request Service

Please fill out the form below to request an estimate or schedule service.

"*" indicates required fields

This field is for validation purposes and should be left unchanged.
Google Rating
Based on 734 reviews

Schedule Service

"*" indicates required fields

This field is for validation purposes and should be left unchanged.