Global Service Horizons systems - "Be sure to check with your supplier to ensure you have the correct vales for the vehicle application you're working on." * Field reports indicate some sealant chemicals added to MVAC systems to reduce leaks have swelled rubber seals, resulting in premature compressor failures and other concerns. - "Note that refrigerant identifiers cannot detect these chemicals. Also, because modern fitting and flexible hose design has already significantly reduced leaks, the need for these chemicals is questionable. MVAC professionals should also remember that incorrect lubricant and/or refrigerant A/C system charge amounts can reduce cooling performance. have a built-in refrigerant identification signal. The need to ensure R-1234yf machine does not become contaminated was recognized after market introduction, so SAE revised J2843. New certified units are now required to have refrigerant identification equipment that identifies and blocks the recovery of refrigerant from a MVAC system that would contaminate the machine. All older machines that do not meet the new J2843 standard will not be recertified. Production of those units has been discontinued. These machines are expensive; it is important that MVAC professionals confirm whether the equipment they purchase meets the latest J2843 require- ments." * Many complaints have been received about the longer procedure times for R -1234yf charging process as compared to R-134a. - "The longer time is a necessary evil that addresses safety, prevents a partial refrigerant charge, and conducts two different leak rate tests. A MVAC system cannot be completely charged without successfully meeting both leak rate test requirements. This procedure is to minimize your liability should the system have a leak that releases the mildly flammable refrigerant into the passenger compartment." R-1234yf Service and Equipment Issues * Some believe the vehicle "trash can" label on evaporators means they must be scrapped during any refrigerant service. - "This is not true; evaporators can be re-used, provided they are not damaged or leaking. Remember that a leaking evaporator on an R -1234yf (mildly flammable refrigerant) system may release refrigerant into the passenger compartment and must be replaced, to minimize your liability and meet regulatory compliance." * Uncertainty in the field regarding the two types of R -1234yf R&R/charging equipment that have SAE J Standard Certification must be resolved - "The first SAE J2843 certified R -1234yf machines do not May 2017 * ACTION 27http://www.omega-usa.com