ACHRNEWS

R-410A: Fact And Fiction

February 2, 2003
[Authors’ note: The information presented in this article addresses several specific safety aspects of refrigerants, but should not be used as a substitute for proper training or following of a manufacturer’s safety instructions. Honeywell recommends that technicians be fully trained and read all relevant safety instructions before using any refrigerant products or working on any systems containing pressurized refrigerants. Readers should not assume that all safety measures are indicated, or that other measures may not be required.]

There are over a dozen brands of R-410A-based air conditioners and heat pumps available today, and more coming on to the market each season.

R-410A has different physical properties than R-22 and technicians should be aware of the differences. But there are also a number of misperceptions about R-410A. The following is aimed at putting to rest some of the myths about this refrigerant.

Myth No. 1

The higher pressure of R-410A makes it less safe than R-22.

Although the pressure of this refrigerant is about 60 percent higher than R-22, the systems, components, service tools, and refrigerant cylinders (both new and recovery) are all designed to safely handle this pressure with a safety margin similar to that for other refrigerants, such as R-22. With over a million R-410A-based air conditioners operating worldwide and nearly a decade of field testing and product history, there is no evidence to suggest that R-410A systems are any less safe than systems that contain R-22.

Educating contractors about the benefits of R-410A was a focal point of the Honeywell International-Genetron Refrigerants booth at the recent International Air-Conditioning, Heating, Refrigerating Exposition (AHR Expo) in Chicago. (Photo by Dave Wilks.)

Myth No. 2

R-410A isn’t the final refrigerant, and there are other refrigerants coming to replace R-22.

For new equipment, this is unlikely to be the case. Every major manufacturer of air conditioners and heat pumps in the United States and Japan has introduced R-410A systems or has selected R-410A as the replacement for R-22. Equipment manufacturers selected R-410A after over a decade of research that looked at many different options to meet the criteria for a refrigerant for new equipment. Some of these criteria included:

  • Efficiency and size: Use of R-410A results in a more cost-effective system than any other R-22 alternative refrigerant especially for high-efficiency systems. This means that an R-410A system can be designed that uses less refrigerant, less copper, and a smaller displacement compressor than an R-22 system.

  • Fractionation: Although R-410A is a blend of two components, it acts like a single component refrigerant, so the control of its composition during transfer and charging is not a problem. Other R-22 replacement refrigerants have “glide,” which makes handling and recycling difficult and expensive because the refrigerant can change composition when it is transferred from one container to another.

  • Safety: R-410A has the same safety classification as R-22 (non-flammable and low toxicity) and does so without the use of potentially flammable hydrocarbons that are found in some other R-22 replacements.

  • Global standardization: To-day’s air conditioning market is becoming more global every day, and equipment manufacturers have expressed a preference to have a single refrigerant that they can use in Asia, Europe, North America, and around the world. Because other parts of the world are farther along in phasing out R-22 than here in the United States, R-410A is more widely used, especially where there are energy efficiency regulations that make it more attractive.

    Myth No. 3

    The higher pressures of R-410A cause air conditioners to break down more often.

    Recent statements by equipment manufacturers indicate this is not only untrue, but that R-410A air conditioners may be remarkably more reliable than air-conditioners that use R-22. There are several factors that appear to contribute to these findings:

  • Air-conditioners that use R-410A are designed to be heavier-duty, with a thicker compressor shell, and often with heavier-duty piping. This results in equipment that may be better able to withstand the vibration that can cause refrigerant leaks.

  • Although the discharge pressure is higher than R-22, the suction pressure is also higher, resulting in a compression ratio about the same or slightly lower than R-22. This, along with some of the thermal properties of this refrigerant, allows the compressor to run slightly cooler.

  • The use of liquid line filter-driers is common practice for R-410A systems, where they have typically only been available on higher-end R-22 systems before. This has contributed to keeping R-410A systems cleaner and drier and reduced the buildup of harmful acids.

  • Air conditioning manufacturers usually require additional training before a technician or contractor can install or service a R-410A system in order to maintain the longer warranties demanded by consumers today. As a result, the dealers and technicians that offer and install R-410A are often better trained and have the right tools to provide a more reliable installation.

    Myth No. 4

    Cylinders of R-410A are unsafe to carry in your service truck. There is even a warning not to exceed 125?F on the cylinder.

    This warning appears on nearly all small refrigerant cylinders, including R-12 and R-22. The safety standard has been in place for many years and has been an industry-accepted warning since the earliest days of fluorocarbon refrigerant use. The U.S. Department of Transportation (DOT) establishes regulations for cylinders that contain compressed gases, including liquefied refrigerant gases, and the higher pressure of R-410A was taken into account when the cylinder design was selected.

    Proper cylinder handling and storage has always been a prerequisite for safe use of refrigerant gases, and keeping cylinders out of direct sunlight and avoiding poorly ventilated or hot locations have always been a required practices for safe cylinder storage. If any refrigerant cylinders are put into a vehicle for transport, adequate ventilation is necessary to maintain safe temperatures below 125 degrees F.

    Myth No. 5

    The pressure of R-410A is so high that if your hand gets in the way of a leak, it could cut a finger off.

    This is a myth, as well as a physical impossibility. Devices such as insulin jet injectors require 7,000 to 10,000 psi pressures to puncture the skin and 16,000 to 25,000 psi pressure spikes are normally used. R-410A does exhibit pressures approximately 60 percent higher than R-22, but these pressures in an operating system will rarely exceed 400 psi.

    The refrigerant R-402A is one of the most widely used refrigerants used in commercial refrigeration and exhibits pressures more than 30 percent higher than R-22, but experienced refrigeration contractors have learned that this makes little difference in the safety of the product in day-to-day usage.

    It is good practice to never place any body part or object in the path of a leaking pressurized gas, no matter the leak rate or pressure.

    Myth No. 6

    The lubricants used with most R-410A systems will absorb so much moisture that if you fill a glass half-full with POE oil and come back an hour later, the glass will be half full of water.

    This is another myth. Although polyolester (POE) oils used in most R-410A systems are more hygroscopic, or water-absorbing, than mineral oils, the typical POE oil becomes fully saturated with water at 0.2 percent to 0.3 percent, which is not enough to notice when visually inspecting a container of the lubricant.

    Should moisture get introduced into an R-410A based system, the filter-drier is designed to remove this moisture before it can react and create harmful acids, which is why these devices are almost universal on R-410A systems. The advertised reliability of new R-410A systems compared to new R-22 systems indicates that this approach has been successful. Even so, steps should be taken to reduce moisture contamination and therefore extend the life of the filter-drier.

    For example, it is theoretically possible for moisture to be absorbed into POE oil through a thin wall of certain types of plastic, which is why contractors are advised not to store POE oils in plastic containers. Most equipment manufacturers have their own guidelines for how long an R-410A-based system should be left open to the air in order to limit the absorption of moisture, and these guidelines should be followed to maintain warranties.

    Mark Spatz is manager, Refrigerant Technical Services and David Metcalf is marketing manager, both for Honeywell’s Genetron® Refrigerants.

    Publication date: 02/03/2003