R-422C: A retrofit blend that is designed to match R-502, R-404A/507 refrigeration systems. Equipment that was previously retrofitted with R-402A/B or R-408A can operate with a replacement charge of R-422C. The hydrocarbon component in R-422C 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.