A/C Service: Then and now

Jan. 1, 2020
The Air Pollution Control Act of 1955 was the first act of federal legislation addressing air pollution and environmental damage. Since then, there have been many changes and ammendments. All of these have affected how we can service mobile A/C syste

Remember the transition from R12 to R134a? Here we go again.

The Air Pollution Control Act of 1955 was the first act of federal legislation addressing air pollution and environmental damage. It provided funding for research on air pollution causes and impacts. The Clean Air Act of 1963 was the first federal legislation that addressed air pollution control. The enactment of the Clean Air Act of 1970 took its predecessor one step further by giving the federal government the power to enact regulations that limited the pollutant emissions from both stationary and mobile sources.

Since then, changes to the Clean Air Act of 1970 have been in the form of amendments. Those made as part of the 1990 amendment package led to the phase out of R12 as an automotive refrigerant and, while not specifically requiring the same, ushered in R134a as the global replacement for mobile air conditioning systems. It also established many of the requirements for service equipment; record keeping and technician certification, just to name a few.

Let's look at some options that were considered along with HFO-1234yf and what you need to know about this newly official R134a alternative.

A Look Back

R12 is a chlorofluorocarbon (CFC), and this family of chemicals was found to be one cause of a depleting ozone layer. If you remember your Section 609 certification testing, you know that loss of stratospheric ozone leads to all sorts of bad things tied to increased UV-B radiation. Increased rates of skin cancer, cataracts and suppression of the human immune system are just a few of the side effects of increased exposure to this radiation. In September of 1987, the United States and 22 other countries signed what became known as the Montreal Protocol, calling for an immediate reduction in the production and use of chemicals known to damage the earth's ozone layer.
By the time the 1990 amendments were added and final rulings enacted, a total of 75 countries had added their names to the agreement. Now, well over 150 have signed on to the Protocol. In June 1990 the Protocol was modified to call for the total global phase out of this type of refrigerant by January 2000. Production of R12 in the U.S. was halted in 1996, yet a Google search still pops up several sources of what is claimed to be R12 refrigerant. Beware of these sources if you are still working on the few R12 cars that are out there. Most are likely hydrocarbon blends that you really don't want in your customer's car, let alone your service equipment.
Now let's fast forward to 2006. The European Union has determined that R134a, our replacement for R12, is a contributing agent to global warming and enacts the MAC Directive. It seems that R134a vented to the atmosphere stayed there a long time before degrading into harmless elements. About 17 years, since you asked. And R134a released into the atmosphere from, say, my hometown, would spread over the entire planet in about a year. To address this problem, they decided to ban the use of any automotive refrigerant with a Global Warming Potential (GWP) over 150 effective with new model platforms offered for sale in their markets in the 2011 model year. R134a has a GWP of 1430, so the search for a new alternative began. Several options were considered.

One of the first was R744, more commonly known as carbon dioxide. It looked to be an excellent choice. With a GWP of zero it should meet today's requirements and those of nearly any possible scenario in the future. After all, it doesn't get much better than zero, does it? But there are some drawbacks. R744 systems operate under extremely high pressure, and most proposals suggested that a system design called "secondary loop" be used to keep those high pressures under the hood and out of the cabin. In this system, the carbon dioxide refrigerant would be used to cool a liquid coolant (antifreeze) that would then be pumped through a heat exchanger in the passenger compartment. This would require a totally new design and take up more space than systems in use today. That means added expense in design and manufacturing costs to the OEMs.

While all reputable sources seem to be telling us that we won't see R744 in production, it is still on the EPA docket for final ruling on adding it to the Significant New Alternatives Policy (SNAP) list, with that ruling expected this summer. Looking into the crystal ball, and considering how much money some OEMs have put into the research, don't count it out quite yet.
Another candidate was the rather short lived R152a. With a GWP of 130, it meets the EU requirement and it is a gas you're already familiar with. It's the same refrigerant found in those aerosol cans you use to clean your computer keyboard. One minor problem, though: it's flammable. And while it could be used in system designs we already have, the thought of flame shooting out of the center vents likely doesn't rest well with corporate legal departments, who would likely insist on the use of secondary loop systems for this choice as well. While it has been added to the SNAP list, don't expect this one to make to the finish line.
All in all, 10 different choices have been investigated as an R134a alternative, with the last submission taking the early lead. This current replacement of choice is HFO-1234yf, also properly referred to as R1234yf, a refrigerant with temperature/pressure characteristics very close to those of R134a, making it almost a drop-in replacement. It, too, is a flammable gas, albeit classified as "mildly" flammable. GM already has announced that it will use HFO-1234yf in some of its 2013 model year offerings, and it is highly likely some European 2012 models entering the U.S. this fall will be cooled by the new refrigerant. The biggest hold up was the addition of HFO-1234yf to the EPA SNAP list of approved refrigerants, but that final obstacle was overcome the end of February 2011 when the EPA issued its final ruling approving HFO-1234yf for use.

And That Means What to Me?

We've been waiting for some firm decisions for some time now, and now that we have them, the reality of dealing with a new refrigerant may catch some of us off-guard. If new models equipped with this refrigerant will be appearing this fall, how do we prepare?

The first question you need to answer is, "When do I expect to have to work on these models?" If you're a dealer, the answer is pretty darn soon. The same thing applies to collision repair shops, and shops that do a lot of automotive A/C work. Even if you don't fall into any of these categories, it won't be long before you'll see them in your shop, so now is the time to prepare.

The first sticker shock you'll get is the cost of the new gas. While Honeywell/Dupont, the makers of R1234yf, have not yet issued a firm price, the most recent estimates predict the cost of a 30 pound cylinder to run approximately $2,000. Needless to say, you'll want to make sure none is accidentally lost when servicing these vehicles.

You'll need new equipment, not the least of which is a new recovery/recycle/recharge (RRR) machine. The SAE standards are in place, and specify a few features over and above what the current J2788 R134a machines have. These RRR machines will have additional internal fans to keep the cabinet vented of any possible accumulation of R1234yf, and also will require that any car connected first be tested with a refrigerant identifier to make sure that what is being recovered is indeed pure R1234yf.

The introduction of anything else into an R1234yf RRR machine may be seen by the equipment as a non-condensable gas (air) and could trigger an automatic purge that would release your expensive stock to the atmosphere. Even worse, while the pressure in the source tank initially would drop, after the purge the pressure would again rise, possibly triggering another release and then another, until that expensive tank of 1234yf was emptied.

Neutronics recently announced that it has developed an HFO1234yf identifier that will act as a simple "pass/fail" analyzer capable of determining whether the sample meets or exceeds the 99.5 percent minimum standard. Currently, though, they are available only in the European market, first available to the OEMs who have warranty responsibility for these cars. U.S. models will meet the new SAE J2912 and J2927 standards for HFO identifiers, and Neutronics also told Motor Age that it will offer a software update to its customers who already own one of the Ultima ID products, making them at least capable of identifying the presence of R1234yf. It will not, however, be able to provide a percentage display of the refrigerant's purity.

In addition to a new RRR machine and identifier, you'll need a new leak detector as well. If you, like me, recently added a new identifier meeting the latest J standard, you may be OK. Add it all up, and preliminary estimates given to us at this year's Mobile Air Conditioning Society's (MACS) convention, expect to invest between $3,500 and $6,500 for the equipment you'll need.

Is That It?

Not quite. Along with the recommended standards for system design and service equipment, the SAE committee recently released all of its new recommended standards. Many were included based on lessons learned in the R12 to R134a conversion process. According to information collected by the committee, nearly 38 percent of the R12 fleet converted even to minimum requirements was done improperly.

David Diggs, global manager of Honeywell's refrigerants, in an e-mail response to this and other questions, says, "The studies regarding the use of HFO-1234yf for the retrofit of existing automobiles are not yet complete."

But Ward Atkinson, chairman of the SAE Interior Climate Controls committee, shared preliminary findings at this year's MACS convention in Orlando. He showed that retrofitting R134a to R1234yf would not be cost effective, and the minor, yet important, design differences between the two systems would make the older systems less efficient if using the newer gas. Besides, who would want to swap over to a refrigerant that costs more? So expect to see no plans on retrofitting. Instead, SAE recommendations favor a natural phase-out as cars equipped with R134a age out of the fleet.

Training technicians, though, is still open for ruling. "The current Significant New Use Rule (SNUR) issued by the EPA only allows certified individuals to perform service on HFO-1234yf systems. The impacts of improperly servicing an HFO-1234yf system and introducing air, water and/or other contaminates are the same as with other refrigerant systems," Diggs wrote.

SAE is recommending additional training and certification, and I suspect the EPA will add that to a later ruling. Interestingly enough, the new training standards include R744.

Another new standard will be focused on evaporator design and construction. New evaporators will have to meet an independently certified standard for use in HFO systems, and the goal is to make them more durable and less prone to leakage caused by external corrosion. Included in the recommendations are requirements that replacement evaporators be limited to those that meet the certification — no salvage yard replacements or repairing of the existing core.

And while there's lots more I can share, let's end this month's discussion on the current state of the small, parts store DIY can. Many in the industry blame the current demand for a lower GWP refrigerant, in part, on the DIYers access to R134a in these cans. The amount of R134a in the atmosphere has grown disproportionately to the number of R134a equipped vehicles on the roads around the world. The only logical assumption is that R134a is being vented to the atmosphere during service.

Many states have already enacted laws requiring special valves on these small cans and their return for recovery when used. Under current EPA rules, only large containers are approved for storage and delivery of R1234yf, making small cans illegal. And some in the aftermarket saw that coming, filing a lawsuit last fall to make it legal to sell to a backyard mechanic.

Considering the flammability issues and costs of the new gas, another real concern is the "topping off" of these newer systems with R134a, resulting in system contamination and likely component damage. With today's Internet sources, it isn't hard to imagine someone offering an adaptor kit allowing the R134a cans to fit these newer designs. What consumer won't want to save a few bucks?

We've been reporting on the coming of a new refrigerant, and now it's here. And who knows yet, there might be more than one to deal with. But for now, focus on preparing for the coming of HFO-1234yf to your shop.

About the Author

Pete Meier | Creative Director, Technical | Vehicle Repair Group

Pete Meier is the former creative director, technical, for the Vehicle Repair Group with Endeavor Business Media. He is an ASE certified Master Technician with over 35 years of practical experience as a technician and educator, covering a wide variety of makes and models. He began writing for Motor Age as a contributor in 2006 and joined the magazine full-time as technical editor in 2010. Pete grew the Motor Age YouTube channel to more than 100,000 subscribers by delivering essential training videos for technicians at all levels. 

Connect with Pete on LinkedIn.

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