THEA/C SERVICE REPORT:

Transcription

1 26 April 2010

2 Photoillustration: Harold A. Perry; images: RTI, SPX/Robinair, Techno Tools, Wieck Media & Thinkstock THEA/C SERVICE REPORT: Good News First BY PAUL WEISSLER The time for the next great automotive refrigerant changeover is drawing closer, and there have been several developments to the story since our last report. If you don t like change, some of them may make you a tad uncomfortable. The good news first, before we tie up some loose ends. The new refrigerant will definitely be R- 1234yf nothing else. There will not be a carbon dioxide system (called R-744 when CO 2 is used as a refrigerant). The last holdout had been the German auto manufacturers. They realized it would be prohibitively expensive and would create international difficulties with system service, so rather than go it alone, they ve mothballed R-744 development work. That s one less thing to worry about. Second, R-134a isn t going away. The R- 1234yf systems will be phased in, and we have no information that says the phasein will be particularly fast. Furthermore, as we noted last year, there will be no retrofitting from R-134a to R-1234yf, so we ll have to continue to deal with R-134a issues, including those involving the electric-drive compressor hybrids. Now, a loose end: Will R-1234yf be sales-restricted to professionals? Will there be any enforcement? The simple fact is that at this moment, R-1234yf can t legally be used even as a mobile a/c refrigerant, because it doesn t appear on what s called the EPA s SNAP List (Significant New Alternatives Policy). The EPA doesn t say whether refrigerants work well or not, just whether they re nontoxic, for example, and not harmful to the environment. Even a highly flammable refrigerant might legally be used with some April

3 pretty enormous safeguards not likely to be incorporated, although some states prohibit the use of flammable refrigerants, period. If a refrigerant fits the allowable bill, it can go on the SNAP list. The government mandates legally required proposals and comment periods from the public and many agencies, and nothing gets rammed through in the middle of night. So a SNAP listing for R-1234yf won t come until fall of this year at the earliest, and maybe not until midwinter. Before systems with electric-drive compressors are recharged, most machine manufacturers recommend a flushing procedure, and equipment for R-1234yf systems, like those meeting updated SAE standards for handling R-134a systems. In this sample of a possible label for R-1234yf systems, notice the flame symbol at top center, for the flammable refrigerant, and the wrench at right, indicating that system service should be performed by a trained technician. J639 is the SAE safety standard for all mobile a/c systems, J2842 is the forthcoming evaporator certification standard and J2845 is a training standard to which the servicing technician should be certified. Photo: Paul Weissler Background art: Harold Perry; images: Thinkstock One of the things the EPA should do is make illegal the use of other SNAP-list refrigerants (mostly blends) on R- 1234yf systems for retrofit. In fact, delisting all refrigerants but R-134a and adding R-1234yf would be the way to go, with no retrofitting permitted for either refrigerant. The SNAP listing also will carry a caveat, because R-1234yf is minimally flammable and the EPA requires there be ways to mitigate even the tiniest risks. Furthermore, because some states forbid flammable refrigerants, their laws have to be modified to allow R-1234yf. The EPA also has to issue a Significant New Use Rule for R-1234yf concerning potential health issues with significant inhalation exposure. The process for this carries a government rule sequence, too. All this is leading up to required certification for technicians to be allowed to service R-1234yf systems, likely to be according to a forthcoming new SAE standard, J2845 Technician Training for Safe Service and Containment of Refrigerants Used in Mobile A/C Systems. To our knowledge, no new plants to make R-1234yf have been built, and the chemical companies have been tightlipped about this. They know they ll have to supply the stuff, and apparently are quietly modifying existing production facilities. However, you can be sure that the changeover will be made as quickly as feasible, as low-global-warming refrigerant (along with efficiency improvements and low-leak system designs) provide Corporate Average Fuel Economy (CAFE) credits that the carmakers need. The first vehicles with R-1234yf systems are expected to roll off the production lines in mid to late summer of next year. And because anything can happen from the first day they hit the streets onward including auto accidents not covered under warranty everyone has to be ready to service these new systems from the start. The SAE engineering standards are being completed for everything from new shop equipment to new components to underhood labels to the refrigerant tanks. And that brings us to the first piece of bad news. The first systems will be those with very small capacity 14 to 18 oz. because the new refrigerant is expected to be a budget-buster, at the outset anyway. We ve been hearing prices at the deepwholesale, large-quantity level of $100 per kilogram, or about $45 per pound. That might translate to a much higher number at the small-quantity shop level. No way will a shop be able to justify dropping around 2 grand to buy the traditional 30-lb. jug. At the moment, the EPA has been looking at a 20-lb. size for a refillable jug, and there s an industry 30 April 2010

4 effort to look at smaller tank sizes to provide flexibility. Even 15 lbs. would represent a major outlay for an independent shop. This is another loose end. Recycling R-1234yf Like R-134a, R-1234yf must be recovered and recycled, so add in the price of a brand-new recover/recycle/recharge machine. We can tell you it will cost somewhat more than even the latest machines that meet the SAE J2788 Can-tap refrigerant adapters have long been available for use with small cans, and they can lead to misuse and mixing of refrigerants in a vehicle s a/c system. Bright Solutions new precision-chamber a/c trace dye injector accepts 8-oz. containers but can dispense exact-measure doses as small as 1 8 oz. Photo:s Paul Weissler standard as listed in the Clean Air Act. Why? As noted, R-1234yf is minimally flammable, and all equipment that handles it must be designed to deal with any possible safety issues. That means arc-resistant switches, solenoids and motors, special venting provisions, temperature limitations within the machine under worst-case scenarios and more. Engineering to get a machine to pass the whole battery of special tests, along with some special requirements, is not cheap. And might shops have to finance a new machine supplied with a tank of the new refrigerant? The whole situation is very fluid because of the uncertainty of the price of R-1234yf. At this point we haven t heard a solution that will make things easy for the shop trying to sell a/c repair to the retail customer. And if you want to hold off on buying a new machine, you may be thinking: R- 1234yf is supposed to be the low-globalwarming refrigerant. Even though it s expensive, what s the legal problem if a system is nearly empty and we just vent what s left? How could we be harming the planet? Here the chemistry gets complicated. Aside from cost (and you can t really put cost aside), R-1234yf does break down in the atmosphere, and one of the products environmentalists worry about is trifluoroacetic acid (TFA), which in significant amounts could be considered a plant growth inhibitor. The atmospheric yield of TFA from R-1234yf is significantly higher than from R-134a. That s one reason why venting remains illegal. Another loose end: How to prevent (or at least significantly discourage) people from recharging the R-1234yf system with something else that s cheaper. We know that cross-contamination may create unpleasant effects within a system, and if someone chooses a cheap, highly flammable refrigerant, that s also a danger to a technician. Even if we restrict R-1234yf sales to certified professionals, how do we stop do-it-yourselfers and others from using something else even R-134a. Yes, there will be specific service hose and vehicle system fittings (details to come), so there should be no inadvertent attempts to install the wrong refrigerant. And the underhood label will be distinctive, with icons that indicate flammability and an EPA requirement for training certification, which will be given in clinics and Web seminars. The vehicle systems will be different and the control calibrations specific, because although the pressure-temperature curves are almost the same, R-134a and R-1234yf have different cooling characteristics and density. Professional technicians have been 32 April 2010

5 pretty good about recovery and recycling with R-134a, but the DIY issue is a tough one. The only answers we can even conceive of are unrealistically expensive to implement. The EPA is unable to provide much enforcement anyway, although for the conscientious professional, it has introduced a Climate Protection Pledge. This might help you explain to a customer why you can t just do the cheapest job (see Climate Protection Pledge on page 39). So refrigerant identifiers will become more important for professionals. There will be a new generation of them designed to identify both R-134a and R- 1234yf and warn the technician even if there s a small amount of a hydrocarbon and/or air in the system (perhaps from a top-up attempt). Although it will be possible to modify existing late-model identifiers to indicate R-1234yf, the new ones probably will be what you ll really want. They also will be engineered to better deal with the possibility of flammable refrigerants. And yes, they also Tracer Products new hybrid kit contains single-use doses of a polyol-ester oilbased trace dye. The opaque plastic capsule below the doses of trace dye is used during air purge of a service hose. To the right of the capsule are two metal purge/service fittings; in the foreground is a hose coupler with check valve. UView s oils premixed with dye contain desiccant bags to absorb moisture that may be drawn into the bottles during repeated uncappings. Photo courtesy Tracer Products Photo: Paul Weissler will be more expensive, particularly if they meet the forthcoming new SAE J2912 (hand-held units) or SAE J2927 (units built into recover/recycle/recharge machines) standards. You won t be able to simply recharge a system with a gross leak, because the R-1234yf machine will first perform a deep-vacuum-hold test. If the system passes that, it will inject a small amount of refrigerant (up to saturated vapor pressure) and then perform a pressure decay test. The system will have to pass both tests before the machine will proceed to the recharge function. These two tests pick up only a really gross leak, so finding smaller leaks important with small-charge systems will continue to be the technician s job. We haven t got a firm fix on how well the R- 134a electronic leak detectors, made to meet SAE J2791, will work with the new refrigerant, although preliminary tests indicate they should identify a gross leak pretty well. Most shops back up electronic leak detection with (or use primarily) trace dyes, and more are installing trace dye as a so-called finishing touch to a repaired system, to ease diagnosis of any future leakage. Each year we see product enhancements at the Mobile Air Conditioning Society s annual trade show, and 2010 was no exception. Although their lab work with R-1234yf has long been underway, the trace dye producers still are developing their field service product lines for R-134a. However, they indicate what you can expect when R-1234yf trace dyes reach the market. At the MACS show, Bright Solutions showed a new R-12/R-134a trace dye injector that enables exact-measure injections from a bulk cartridge. Called the Pro-Shot, the all-metal injector has a precision-sized internal chamber that holds 1 8 oz., so, depending on the system, a technician can inject once for 1 8 oz., twice for 1 4 oz. The injector holds the standard 8-oz. cartridge and comes with a service hose that has a dual coupling (R-12, R-134a); when the R-1234yf specs are out, we ll probably see an adapter for that, too. Tracer Products featured its new trace dye kit for R-134a hybrids with high-voltage compressors. These use a 34 April 2010

6 POE (polyol ester) oil, and Tracer s TP kit comes with three dye capsules and a short hose/coupler to hold the dye capsule. The kit also includes a purge fitting and capsule to clear air from the service hose prior to dye injection, which is done with liquid refrigerant from a recovery machine or gauge manifold setup. UView showed its polyalkylene glycol (PAG) and POE oils premixed with Refrigerant can be used to remove oil from service hoses, and the internal plumbing of a recover/recycle/recharge machine uses a fitting to join the couplers of both hoses. When the hoses are joined, many machines use revised software to initiate a refrigerant flush, as indicated by the digital display seen here. trace dye. The oils are in 16-oz. containers, which include desiccant bags to keep the oil moisture-free during multiple uncappings. You might think that 16 oz. is just enough for two systems, but additions for just replacing a heat exchanger or a compressor might be a couple of ounces. And even a complete oil replacement on a late-model system might be as little as oz. The dye premix is intended for those systems that already contain dye, or are getting a full charge of oil. An ounce or so of premixed oil/dye is not going to be enough dye by itself, if diluted by oil without dye already in the system. More bad news: Although the R- 1234yf belt-drive systems will use PAG oils, they apparently will be different from the ones for R-134a, so you ll have to keep a separate stock. Maybe we ll eventually get compatible PAGs. The original equipment evaporators installed in R-1234yf systems will be super-robust designs, to avoid the risk of a level of leakage that could introduce a flammable mixture of R-1234yf into the passenger compartment. The evaporators will have to meet a new SAE standard J2842 which subjects production-intended prototypes to pressure and temperature cycling tests and corrosive sprays, to ensure survival in the worst automotive environment. The SAE standard specifically mandates no repair of leaking evaporators, and aftermarket evaporators engineered for R- 1234yf systems will carry a label saying they meet J2842. The standard does not apply to R-134a evaporators. Electric-Drive Compressors in Hybrids We left this question open last year; let s answer it this year. The problem, for those who ve forgotten, is that in Circle #24 36 April 2010

7 instances of multiple service, a system with an electric-drive compressor in a high-voltage hybrid could suffer oil cross-contamination. That is, PAG oil in the plumbing and services hoses of a recycling machine could get into a hybrid, contaminating the POE oil when the machine goes from servicing a belt-driven compressor system to an electric drive. Doesn t take much to create a problem 1% PAG in a POE system lowers electrical resistance significantly through the compressor. And this could result in a no-start from a ground-fault trouble code, or high-voltage shock danger to a technician touching the compressor in the first few seconds of operation. The way to prevent this is to have some provision to clear the PAG oil before a high-voltage compressor is serviced, or filter it out during a recharge. The new standard for R-1234yf machines will require some method for doing this, as will an update to SAE This externally mounted Hybrid Guard developed by AirSept and Norco/FloDynamics filters oil from the lines and hoses prior to recharge. It works with all machines. J2788 for R-134a machines. All the leading manufacturers have a workaround for the cross-contamination issue. At CPS Products, Robinair (for its No machine only), RTI Technologies and Ritchie/Yellow Jacket, it s 38 April 2010 Circle #26

8 Climate Protection Pledge The EPA tries to do most things with voluntary agreements, and the Climate Protection Pledge is its latest example. You agree to the pledge and you can post it, so that when you tell a customer you fix leaks before you recharge a system, you can point to the pledge hanging on the wall. It says plainly that you ll discourage the customer from recharging without leak repair, and that (if you choose to implement one) you have a shop policy against just topping up. The agreement also says you have all the right equipment to do the job, specifically listing each tester, tool and machine. It also asserts that a shop technician has been trained in best service practices. If you do comply, you even can advertise the fact. That should give you credibility against the guy down the block who hasn t signed up. tools and kits manufacturer. It s a recycling machine filter asssembly that protects the machine from sealers and other contaminants that may have been installed in a system, during refrigerant recovery. That filter assembly was redesigned internally, allowing it to be installed to work on the recharge side, so it removes any oil that might be in the hoses and plumbing. Laboratory tests showed it was very effective and saved technician time. This hybrid issue will not arise with forthcoming recover/recycle/recharge machines for R-1234yf. The SAE standard covering them (J2843 for R/R/R and J2851 for recover-only) specifies that they have similar protection against cross-contamination already engineered in. a way to flush the service hoses and internal plumbing of residual oil before service on a hybrid. At Norco/FloDynamics, the approach is an external device that was co-developed with AirSept, an a/c This article can be found online at Circle #27 April