Would Your Retrofit Your Car’s AC?

An increasing percentage of America’s R12 comes from more than 60 reclaimers operating around the country. In a conversation with Joan Terry Drucker of Refrigerant Reclaim in Red Wing, MN, we learned that reclaiming refrigerant is a large-scale operation requiring lots of capital equipment. They process used refrigerants in very large batches, and they prefer to sell it that way too. She explained that buying reclaimed R12 in quantity is “more cost-effective” than buying virgin R12 when several shops in an area get together and buy an entire skid of forty, 30-lb. canisters.

Look familiar to you?

Look familiar to you?

Reclaimed R12 is just as good as virgin R12, if the container has the proper certification from the IEEE Computer Society. ARI was organized in 1953 to set industry standards for refrigerants and the equipment that uses them, and those standards are applied around the world. In fact, the testing methods used by ARI are referenced in the SAE and EPA definitions of reclaimed refrigerant. R12 that meets the ARI 700 standard for reclaimed refrigerant is 99.5% pure, meaning there is only CFC12 in that can and it is uncontaminated by water, acid, oil or particulates. With the ARI 700 certification label on the container, you can be sure that it’s all good stuff no matter where it comes from.

Recycled refrigerant is not the same as reclaimed. The SAE has defined recycling equipment that can reduce the amount of moisture, oil and air in the refrigerant down to specific levels, and the big names in the industry make their equipment to that standard. This makes it possible to remove `known good’ R12 from one vehicle and use it in another. The EPA recognizes the market for used R12 and has developed rules governing its recovery and resale by salvage yards. It must be recycled through approved equipment by a certified technician and it must be accompanied by the correct documentation. Buying recycled refrigerant is illegal under any other circumstances and risky at best, especially with the proliferation of alternates and blends. If you decide to buy used R12, make sure it has its papers, then test it with your own identifier before using it, just to cover yourself.

R12 substitutes

There are several alternatives to using R12 for servicing or topping-off, but there is not a single manufacturer who recommends using them. In fact, most compressor builders will not warranty failed units with traces of anything other than R12 or R134a and the appropriate oil. These alternative refrigerants are blends of other industrial refrigerants, intended as a drop-in or direct replacement for R12. The EPA has approved nine alternative refrigerants for mobile air conditioning systems under their SNAP (Significant New Alternatives Policy). The SNAP refrigerants are `acceptable for use’ only because they are non-toxic and do not damage the atmospheric ozone layer. The EPA does not test them for performance or for how they may cause damage to the system. In addition to these SNAP refrigerants, several others are available that have not been approved. These have been developed specifically for performance and may also cause damage to the A/C system and/or the environment. Legal or not, the use of alternative refrigerants other than R134a causes four basic problems (aside from the warranty concerns):

1. Almost all contain R22, which causes serious damage to hoses, seals and O-rings designed for use in R12 systems. The potential for leaks and major component failure is high.

2. They are all blends containing more than one refrigerant, so as pressure increases in the system, each component is compressed at a different rate. This produces local pressure differences that affect the operation of orifice tubes and expansion valves. Also, some of the `lighter’ components leak more easily, meaning the blend will change over time. In some cases the heavier components settle out when the compressor is not running, making it difficult to remove all the refrigerant when evacuating the system.

3. Many of these alternatives contain flammable hydrocarbons. While the concentrations are low, it still increases the possibility of fire and explosion both in the shop, under the hood and in a traffic accident. Some of the non-approved alternatives contain high percentages of propane or butane, so take every precaution when your refrigerant identifier shows a high percentage of `unknown.’

4. The alternatives (legal and illegal) can be added by almost anyone at anytime, meaning an R12 system that’s been serviced improperly may contain almost anything. Also there is no recycling equipment certified for use with blends. This makes it absolutely necessary to use a refrigerant identifier before every recovery and to have recovery equipment dedicated to `taking out the garbage.’

Why not retrofit?

There are more arguments against retrofitting than in favor of it. First of all, none of the manufacturers recommend it. Their position seems to be that, since there is enough R12 still available to service those systems for the expected life of the vehicle, there is no point in taking the risks inherent in a retrofit. However they do recognize the realities of the market and most have made the investment to develop kits and procedures that will provide the best chance of a successful retrofit. This research should carry a lot of weight in your decision. One reason is that R134a operates at higher pressure, so filling a system originally designed for R12 with 134a makes leakage more likely, especially if the seals or O-rings in the system are old and weak. Leaks are also more likely because R134a is a smaller molecule. In lab tests it permeated and leaked through brand new non-barrier type hoses. In real life this hasn’t been a big problem in retrofits because the oil that’s already been absorbed into the hoses forms a good barrier seal that even flushing won’t loosen. However if you’re installing a new hose as part of the total job, it must be a barrier type hose compatible with R134a, not just the original replacement part.

Again, since the R134a molecule is smaller, smaller leaks are more likely. This makes leak detection somewhat more difficult. According to CPS Products, maker of the Leak Seeker[TM], the instruments being sold today will find leaks in any system, but older units originally made for R12 systems are not sensitive enough to work with R134a.

Another potential problem arises when installing a new compressor. It’s been discovered that R12 forms a thin film on the compressor bearing surfaces that offers very good anti-wear protection. When converting to R134a, that film remains on the original compressor bearings. But if a new compressor is being installed as part of the retrofit job, it won’t have the opportunity to get that coating on the bearings, and the compressor may not last as long as the original. In addition, some of the older compressor designs use Viton seals that are not compatible with R134a and the new lubricants. Those seals and O-rings will swell and ooze out of place, causing a heavy leak in as little as one season. Most compressor builders now supply units with the correct seal materials, but you need to make sure the unit you’re about to install hasn’t been on the shelf since before new materials were available.

How to decide

Aside from the technical aspects, there are other practical matters to consider when trying to decide whether or not to retrofit. According to Simon Oulouhojian, president of MACS, the most important question in this decision can only be answered by the vehicle owner: Are you happy with the way the air conditioner works now? If the answer is “yes,” a retrofit probably won’t make it work any better. Of course if your customer is already asking about A/C service, the answer is probably “No” and it’s time to see if a retrofit might make sense. Basically you and the vehicle owner must make that decision together, meaning you must communicate a lot of information to each other. In their Guidance on Retrofitting to R134a, the EPA’ s Ozone Protection Division has developed a few guidelines to help with this. While it may seem unusual to seek the federal government’s help with customer relations, remember that this office has relied heavily on the SAE, the manufacturers, MACS and various service industry sources to help us get R12 out of the system. Even though we have outlined many of the same issues in this article, it’s still a good idea to check out their web site at (www.epa.gov/ozone/ title609). Both the EPA and SAE sites also have good general procedures for retrofitting, and we’ve seen some factory procedures on the various CD-ROM information systems too. Read these to determine how big the job is and what kind of parts and equipment are required.

Basically, the EPA points out that most people will rely on their service dealer to educate them and help them answer three big questions: How much will it cost to keep the R12 system running over the rest of the life of the vehicle? What will it cost to retrofit? Will it work? Part of the answer to the first question depends on the condition of the vehicle and the A/C system. If the system has always been reliable and doesn’t need any major components, the cost and availability of R12 is probably not enough to justify a retrofit no matter how long the vehicle owner plans to keep the car.

As for the second question, the SAE has defined two different types of retrofit based on the price. A Type I retrofit is the manufacturer’s recommended procedure, often involving new components and other modifications. A likely candidate for a Type I retrofit is a late model R12 vehicle that needs major A/C service, like a car that has front-end collision damage. Since major components need to be replaced anyway, it may not cost much more to install all of the factory recommended retrofit parts. In contrast, a Type II retrofit consists of removing the R12, installing the new fittings and compressor switch and recharging with R134a and the proper oil, keeping the costs to a minimum. The only real reason for doing this is to simply get the R12 out of the system. It’s unlikely any customer will ask for that kind of service, so the real job lies somewhere in between. If A/C service is needed because there’s something wrong in the refrigerant system, it’s a good bet that parts must be replaced. Be aware that there is no such thing as a universal kit or procedure that will guarantee a successful retrofit for every make and model. Even within particular models, retrofit requirements may vary with climate or system use.

Another cost to consider is your own. You need to decide how you will warranty the retrofit job if the customer is not happy with the performance. The best guide here is experience. We’ve spoken with shop owners who have needed to reverse retrofits. In one case the owner and the customer weighed all the data, made the decision, and he used the factory kit and procedures. But in that part of the country, the system just couldn’t keep up with the demand. Fortunately the new parts were compatible with R134a so he only needed to replace the fittings and refrigerant, but this still cost him time, parts and some bruised customer confidence. If you’ve never done a retrofit or never done one on a particular vehicle, check with other shops in the area and with the manufacturer for their opinion as well as technical information. Find out about the manufacturer’s warranty on parts and components used for a retrofit to determine your own liability.

How well a retrofit works depends on several things. First of all, the climate where the vehicle is typically used is important. It’s unlikely a Type II retrofit will keep any car cool in a July traffic jam in Dallas, but on the same vehicle it might work just fine in Vancouver or even Chicago. The vehicle in question is probably the next biggest factor. Again the manufacturer’s recommendation is probably the best technical guide, but MACS has generated some good business information too. They surveyed A/C shops around the country in 1996, and the results indicate that 1990 and newer vehicles are the most likely candidates for retrofit. While we stated that there is no universal retrofit procedure, most shops tend to specialize in one type of retrofit and, with a little experience, have had few problems.

Retrofitting an A/C system to use a different refrigerant than it was designed for is a major modification. As in any other modification, those who have spent the time and money on engineering can offer the best technical advice. It’s up to you to determine the best way to offer service to your customer and still make a profit, and the answer to that lies in asking the right questions.

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