Auto Service Professional

APR 2018

Magazine for the auto service professional

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30 | ASP April 2018 Technical required for all technicians who will repair or service vehicle air conditioning systems, including the new R1234yf refrigerant. is training will ensure safety for your staff, customers and the environment. Starting Jan. 1, 2018, the EPA has reinforced that those purchasing refrigerant will need to show an EPA-approved 609 certification card. While we are not sure everyone you buy from will ask to see your card, you should be ready just in case. Understanding the changes (e following was supplied courtesy of Peter McArdle, senior master tech and trainer/developer for the Four Seasons Divi- sion of Standard Motor Products.) A/C compressor replacement is one of the highest warranty return repairs. is is primarily due to the root cause of the original failure not being identified and poor repair procedures that result in contaminants from the original compressor failure being left in the system. In the past, most condensers featured tube and fin construction. Today, the industry uses flat-tube/multi-pass, multi-path condensers that feature very tiny tubes, making it diffi- cult, if not impossible, to flush out debris that resulted from the original compressor failure. A clogged micro-tube condenser is one of the most common causes of repeat compressor failure. About 20 years ago, the average refrigerant charge amount was about 44 ounces. Today, the average charge is about 20 ounces. e amount of oil was about 8 to 9 ounces, and today it's about 3 to 5 ounces. Today we are getting the same job done with half the amount of the refrigerant and oil. A/C efficiency has doubled, with improved heat exchange. Evaporator technology has also evolved from tube and fin to flat tube multi-pass, multi-path designs making oil circulation through them and flushing them more dif- ficult. While the drier must be replaced as a mandatory step, if a catastrophic compressor failure occurred, every inch of the refrigerant path needs to be either flushed or replaced. Compressors are not warranted unless the accumulator/receiver dryer and orifice tube has been replaced. Hose assemblies with in-line filters or mufflers cannot be flushed and should be replaced. Quite often lines are contaminated with debris. Because R-134a is a global warming gas, vehicle manufacturers have striven to increase system efficiency to use less of it and also to improve fuel economy and reduce tailpipe emissions. e problem is that today's systems are so efficient that they are somewhat "delicate," requiring increased precision in terms of diagnostics, flushing and charging accuracy. A 2 ounce charging error has double the impact on a 20 ounce system than it has on a 40 ounce system; the same leak results in low charge, oil drop out and compressor failure twice as fast! Once the A/C system's high and low side connec- tions are made, pressure and temperature infor- mation is immediately available on a smartphone or tablet using the ManTooth app. This represents a quick and efficient way to determine if the system requires attention. In this example, the gauges reveal zero pressure on high and low sides. Photo courtesy Ritchie Engineering/Yellow Jacket Products

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