R-422B: A retrofit blend that is designed to match R-22 in air conditioning applications. There is a slight reduction in capacity which would result in slightly longer run times. Systems that were previously retrofitted to R-417A can operate with a replacement charge of R-422B. The hydrocarbon component in R-422B 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 mineral oil and keeps it moving around the loop. More complicated piping arrangements or large hold-up volumes may require the addition of POE.