A blend of R-22 and R-125 with hydrocarbon R-290 (propane) included to improve mineral oil compatibility. This blend is formulated to match R-502 in evaporator temperature ranges and does not significantly increase discharge temperature in R-502 retrofit situations. Discharge pressure, however, can increase from 25 to 40 psi over pressures seen with R-502. Although the propane was added to improve oil circulation it is still recommended that some mineral oil be removed and replaced with alkylbenzene.