A Formula for Failure – Mixing Alternative Refrigerants with R-22

With the dramatic market shift way from R-22 comes the rise of a number of new refrigerant options for technicians to use and distributors to sell.  Many folks in the ACR industry were not prepared for the transition to an alternative refrigerant and the flood of new refrigerant options to choose from, which continues to make their jobs even harder.

The most troubling and fastest growing concern showing up today, is the practice of mixing alternative refrigerants with R-22.  This practice is considered highly unacceptable and irresponsible by the mainstream refrigerant industry for a number of good reasons.  ICOR has received numerous reports from technicians claiming they were told by a distributor, or even worse, a refrigerant manufacturer’s representative, that it is acceptable to mix an alternative refrigerant with R-22.  More than likely, it is the result of selective listening and or miscommunication, rather than a conscious effort by anyone to encourage mixing.

The primary concern with mixing R-22 with an HFC alternative is the unpredictable change in the pressure temperature relationship.  HFC based alternative refrigerant are comprised of no less than two refrigerants, and some have a blend of as many as five refrigerants.  They have been developed in a way that when properly used in their pure form, and in a qualified application, they will mimic the operational characteristics of R-22.  However, even in their pure form (not mixed with R-22) they will not provide adequate performance unless the refrigerant charge has been optimized by using the refrigerant’s respective pressure chart, and the superheat or sub-cooling calculation method.  When an alternative refrigerant is mixed with R-22 there is no pressure temperature chart to refer to and therefore no way to optimize the system charge.  Improper superheat or sub-cooling can lead to compressor flood back, overheating and dramatically reduce system efficiency and compressor lifetime.

Mixing any HFC alternative refrigerant with R-22, in any concentration, is a formula for failure and should be discouraged industry wide.  Any statement made to the contrary is highly irresponsible and the result of either poor communication, inadequate education, or misguided self-interest.

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