Modern Tire Dealer

APR 2017

Magazine for the professional tire industry

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MTD April 2017 Real world experience with R1234yf e new refrigerant is finally here; are you ready? By Jacques Gordon I n 2014, Fiat Chrysler began filling the air conditioning systems on almost all of its models with R1234yf refriger- ant. at same year, General Motors (GM) began using it in the Cadillac XTS. Since then, GM has been gradually switching over its entire line of vehicles to R1234yf, and Ford has also begun using it, too. Much has been wrien about what to expect when the industry changes over to the new refriger- ant, but up until now it was all speculation. Shops that do A/C work for collision repair have been working with R1234yf for three years, and with some 2014 models just starting to come out of warranty now, some independent tire dealers and technicians are finally gaining real world experience with the new refrigerant and the new tools and service techniques. Here is some of what they've learned so far. System hardware Air conditioning systems filled with R1234yf are almost identical to those using R134a, but there are a few important differences. First of all, there is one additional component: an inline heat exchanger (IHX) that has two concentric chambers. Liquid refrigerant from the condenser flows through the inside chamber, and the outside chamber surrounds it with vapor flowing out of the evaporator on its way back to the compressor. e still-cool vapor absorbs heat out of the liquid refrigerant, "sub cooling" it below condensation temperature to improve overall system efficiency. ere are two basic types of IHX. On A/C systems with an orifice tube, the IHX is generally (but not always) built into the accumulator. On an expansion valve system, it's more likely to be a separate part, a tube- within-a-tube that has a pair of inlet/outlet fiings on each end. ere are no moving parts to wear out, so unless it's damaged there's no need to replace one. Still, it's important to know it's there and what it does. Another difference involves the new service ports and caps. e service ports are designed to make it impossible to connect service equipment that's made for systems using other refrigerants. Of course, adapters are available and some shops may actually find a legitimate reason to use them, but we'll discuss that later. Service ports have been identified as a source of refrigerant leakage and air contamination. If the vehicle sits long enough at a low-enough ambient temperature, most of the refrigerant will condense to a liquid and system pressure can fall below atmospheric pressure. is will allow ambient pressure to unseat Timely A/C service can prevent your customers — and their vehicles — from becoming overheated! The bottom photo shows the label on a new Malibu. It is on the fire- wall and indicates refrigerant type and quantity and the correct type of oil. Notice the "flammable" icon. The inline heat exchanger (IHX) is the thick, striped part toward the left of the service port. It will be difficult to use this part of the air conditioning system when using tem- perature readings to analyze system performance. feature 32

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