When charging an R-410A system, follow the manufacturer’s recommendations for their equipment; as with R-22, the superheat method is used when charging fixed orifice systems while the subcooling method is used for TXV equipped systems. (Photo courtesy of Honeywell.)
The transition from R-22 to R-410A is well underway, spurred on by the fact that as of Jan. 1, 2010, cooling equipment can no longer be manufactured with R-22. Even though that transition is just around the corner, some contractors are still leery of using R-410A. They’ve heard the rumors surrounding R-410A and have decided to keep using R-22 as long as possible.
Our own panel of “mythbusters” has agreed to dispel some of the most common rumors about R-410A. Jeff Goss, product manager, Bryant Heating & Cooling Systems, and Ron Vogl, marketing manager, Honeywell Genetron Refrigerants, help clear up the confusion surrounding R-410A.
EXPERTS ANSWER THE QUESTIONSMyth:
R-410 is a blend of refrigerants, so if there is a leak, the entire charge needs to be recovered and the system completely recharged with new refrigerant.Fact:
According to Vogl, “Although 410A (AZ20) refrigerant is a 400 Series blend, it has very small glide and fractionization potential. In fact, R-410A is termed a near azeotrope and performs as a pure fluid; laboratory and field tests show no composition shift in the refrigerant after repeated leak and recharge operations. Good service practices should treat all 400 Series blends equally, and systems should be charged by withdrawing liquid refrigerant from the cylinder.”Myth:
Since R-410A is a high-pressure refrigerant, it will cause more stress on a system, causing an air conditioner to fail or leak more frequently.Fact:
Not true, said Vogl. “Manufacturers must design and build systems and units to a standard, which is based on the operating pressure of the chosen refrigerant. Millions of R-410A systems are in use globally, and manufacturers are reporting excellent reliability and a low number of warranty issues relative to R-22 systems; in fact, reliability has been shown to be better for R-410A systems.”Myth:
R-410A is most likely an interim product and another refrigerant will take its place shortly.Fact:
This refrigerant is not an interim product, said Goss. “In fact, Bryant dealers have been installing systems using Puron refrigerant for over 13 years. Most leading compressor manufacturers have adopted R-410A into their product offerings, and some have even published bulletins listing the shortcomings of so called “drop-in” replacements for R-22. R-410A refrigerant is here to stay.”Myth:
R-410A has not been around very long, so we don’t really know how reliable it will be over the long term.Fact:
R-410A has been around since the early 1990s, with the first commercial unit sold in 1996, said Vogl. “The United States has been slower to adopt this solution than other countries, particularly Asia and the European Union. Not until the higher SEER ratings on residential equipment were imposed did the bulk of U.S. manufacturers begin moving to R-410A. The commercial development of the scroll compressor engineered for R-410A, the addition of filter driers to residential a/c units, and improved installation procedures have all contributed to excellent R-410A system reliability.”
Contractors worry that leaving a cylinder of R-410A on their trucks in warm weather may cause the cylinder to explode. The fact is, if any refrigerant cylinder is left in a hot environment, the internal pressure increases as does the possibility of reaching the pressure relief setting.
Myth: The oil used with R-410A absorbs a lot of water, so can this cause a system to break down.
Fact: According to Goss, the oil used with R-410A systems is more hygroscopic than oil used with R-22. “But with proper training and installation practices, moisture absorption should not be an issue. All of Bryant’s Puron refrigerant systems are supplied with a liquid line filter drier that will dry the system out should it be open to the atmosphere longer than desired.”
Myth: If I leave a cylinder of R-410A in my truck on a hot day, it could explode.
Fact: If any refrigerant cylinder is left in a hot environment, the internal pressure increases as does the possibility of reaching the pressure relief setting, said Vogl. “Department of Transportation- (DOT-) approved cylinders are engineered with three pressure ratings - service pressure, test pressure, and burst pressure - suitable for the refrigerant they contain. For R-410A, these are 400, 500, and 1,000 psig, respectively. The relief settings have a range specified by the DOT and CGA (Compressed Gas Association), and for R-410A, the range is 525 to 800 psig. All Honeywell cylinders regardless of refrigerant are stamped with a warning to not expose the cylinder to temperatures above 125°F; R-410A at this temperature is 445 psig, 80 psig under the low range of the relief valve setting.”
Myth: R-410A is caustic and will eat away copper tubes, causing premature failure. It would be better if manufacturers used stainless steel tubing.
Fact: R-410A is not caustic and manufacturers have chosen materials of construction suitable for both the refrigerant and the lubricant, said Vogl. “Stainless steel could be used in the construction of units, but the good heat transfer properties and workability of copper make it more suitable.”
Myth: R-410A is expensive, and people don’t want to use it until the costs come down.
Fact: R-410A prices are following the laws of supply and demand. “Already there have been indications of price levels more in line with R-22,” noted Goss. “As R-22 phases out and refrigerant manufacturers switch over the majority of their production capacity to R-410A, the price of R-410A should continue to drop, while the price of R-22 is expected to increase.”
Myth: Since R-410A doesn’t have chlorine, I can vent it into the atmosphere.
Fact: Rules imposed by the Environmental Protection Agency (EPA) state that no refrigerant can be intentionally released to the atmosphere, stated Vogl. “Although HFCs contain no chlorine, they have global warming potential and should be recovered and recycled.”
Myth: I can use my ultrasonic, electronic, or halide leak detector to find leaks in an R-410A system.
Fact: Probably the most important consideration in choosing a leak detector for R-410A is that it is rated for HFCs, said Goss. “There are a number of these leak detectors available commercially. While Bryant does not recommend a specific type or brand, it is important to note that halide torch detectors are not acceptable.”
Myth: I can charge an R-410A system the same way I would an R-22 system.
Fact: Goss stated that charging procedures such as subcooling, superheat, and weigh-in methods are the same for both R-22 and R-410A refrigerants. “Proper charging procedure depends on the metering device being used and the indoor and outdoor conditions; however, Bryant does recommend that the system be liquid charged only.”
Myth: Because R-410A is a blend, it can’t be reclaimed and reused.
Fact: R-410A can be reclaimed and reused; however, recycled refrigerant may only be returned to the equipment from which it was removed or used in another device owned by the same person, clarified Goss. “Refrigerant that is too contaminated for reuse must either be disposed of properly or reclaimed. Reclaiming restores the refrigerant to its original state and must be done at a reprocessing or manufacturing site.”
Myth: If I’m replacing an R-22 system with an R-410A system, I can use the same line set and the same type of filter-driers.
Fact: Old line sets can be reused, noted Goss, as long as they are the proper size for the new system. “Bryant recommends removing as much residual oil from the system as possible by draining oil from traps and low spots in the suction line. Bryant also recommends using larger filter driers with a Puron refrigerant system because the polyolester oil is more susceptible to moisture. All of our units are shipped with a filter drier that can be field installed, and we recommend installing the filter drier as close to the indoor unit as possible to protect the expansion valve from residual contaminants.
Publication date: 04/20/2009