The last 30 years have been a bit of a rollercoaster as far as synthetic refrigerants are concerned. First, CFCs were phased out and replaced by HCFCs, which are now in the process of being phased out themselves. HFCs were created to take the place of HCFCs, but they, too, are being targeted for a phasedown and are likely to be replaced by HFO blends. While most a/c and refrigeration systems containing CFCs are no longer in use, contractors regularly work on equipment that utilizes HCFCs, HFCs, and HFO blends, which means they have to stock a plethora of different refrigerants in order to serve the various needs of their customers.
Unfortunately, this growing number of refrigerants has significantly increased the chances of a system being charged with multiple refrigerants. Mixing refrigerants can have an adverse effect on air conditioning and refrigeration systems, resulting in reduced efficiency, performance, and longevity. And it can create a safety hazard for the technician who may not know exactly what type of refrigerant a system may contain.