R-422D: A retrofit blend that is designed to match R-22 in refrigeration applications. There is a reduction in capacity which would result in longer run times. There may also be excessive pressure drop in long piping runs which may limit capacity further. 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 component thins the oil and keeps it moving around the loop. More complicated piping arrangements or large hold-up volumes may require the component of POE.