R-422D is a low and medium temperature retrofit blend for R-22 refrigeration and air conditioning systems. R-422D will show a drop in capacity compared to R-22, which usually translates into slightly increased run times in a properly sized system. Some system components may need to be changed if excess pressure drop develops. The hydrocarbon component in R-422D helps promote oil return in systems containing mineral oil or alkylbenzene. Although HFC refrigerants won’t mix with these oils, the hydrocarbon addition thins the oil and keeps it moving around the loop. More complicated piping arrangements or large hold-up volumes may still require some oil be changed to POE.