Modern Tire Dealer

APR 2017

Magazine for the professional tire industry

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MTD April 2017 Air conditioning service will light more easily and burn hoer than R1234yf, so the industry has determined that with proper A/C system design, it does not increase the chances of fire in the vehicle. Working with the new refrigerant requires a bit more caution. e new service machines are built with ventilation fans and ignition- proof solenoids and switches. If you're going to service the system without using one of these new machines, take the same precautions you would when working with a fuel system. Handling and storage require a bit more caution, too. e refrigerant is available in easy-to-manage 10-pound containers. Even though it's officially classified as "mildly flammable," warning labels on the container indicate the contents to be "highly flammable" because the gas is under pressure. Therefore, requirements for safe handling and storage of R1234yf containers are the same as those for other compressed flammable gasses. • Refrigerant containers should not be exposed to direct sunlight or to temperatures greater than 125 degrees Fahrenheit (52 degrees Celsius). • Containers should be stored in a cool, ventilated area away from any possible ignition sources. • Containers should be strapped into place and protected from physical damage, moisture and corrosive liquids or gases. Service equipment You may already know there are some new A/C service machines on the market designed for use with R1234yf. Here's a quick summary. e newest recovery/recycle/recharge (RRR) machines are designed to SAE Standard J2843, and they have fiings on the hoses that will only connect to vehicles that use R1234yf. e SAE standard describes the major features of the machine: • It will recover 95% of the refrigerant in the system. • It will recharge the system to within 1/2 ounce of specification. • Aer recovering 150 pounds of refrigerant, it will not run again until the onboard filter/drier is changed. • It will have a built-in refrigerant identifier or a USB port to connect an identifier. • It will not allow recovery of contaminated refrigerant. • It will not recharge the system if it detects a leak. • It has ventilation fans and non-sparking switches, motors, relays, etc. e recovery and recharge processes are highly automated and/or fully automatic, but the tech may be prompted to run some tests before the machine moves on to the next step. Some of the new machines used by OEM dealerships have soware that is specific to those brands, so they might not work on different brand vehicles. However, the machines sold to the aermarket are universal. New machines are available that are designed to the same SAE standard but equipped with fiings for vehicles that use R134a. New hoses and fiings can be installed to reconfigure it for servicing R1234yf systems, but it's not a "convertible." Once reconfigured, it can't be converted back to the old refrigerant. is means that a shop needing a new R134a machine now can buy one knowing that it can be converted when they have enough business that requires R1234yf service. Since the new machines will not recover contaminated refrigerant, your shop will need some kind of recovery-only machine. Because R1234yf is mildly flammable, shops should not just use an old R134a machine with fiing adapters; it must be specifically designed to SAE Standard J2851, which applies to recovery-only machines. Some machines will simply be described as "spark free" and that's OK, but the holding cylinder must also be rated for flammable gases. Service techniques Once the machine is connected and the data has been entered, all the tech has to do is follow the prompts on the screen. e machine will identify the refrigerant and then recover the refrigerant (and oil) if it's at least 98% pure. At this point the procedure can be interrupted if the tech intends to remove parts. Before charging the system, the machine will pull a vacuum and watch for vacuum decay that indicates a leak. If the system passes the vacuum leak test, the machine will install 15% of the total refrigerant charge into the system and prompt the tech to run an evaporator leak test. is consists of turning the blower on low, selecting the floor vents and inserting a leak detector probe into the center floor duct. When the tech confirms there is no leak and pushes the "continue" buon, the machine will automatically recharge the system with the correct amount of refrigerant and oil. Finally, it will print a service report that includes the amount of refrigerant recovered and recharged into the system. If the system is already empty, old-school recharging methods still work because the basics are still the same. With the proper gauges, good scales and a vacuum pump, an experienced A/C tech can recharge the system and make it blow cold air. However, for professionals geing paid to do the job, this is not legal. A shop can be fined for doing A/C service without the proper equipment or service reports. Besides, R1234yf refrigerant is so expensive that even a minor leak or accidental loss during service can remove all the profit from the job. e recovery/recycle machines are specifically designed to prevent this. Flushing the air conditioning system with pure refrigerant is a good way to remove excess oil, but it will never reliably unblock a condenser that's clogged with debris from a damaged compressor. Photo courtesy of Hecat Inc. 34

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