Refrigerant R401a, MP39

R401A (also known as MP39) is a zeotropic blend of HCFC-22, HFC-152a, and HCFC-124 designed as a retrofit for R-12 in medium/low-temperature refrigeration and direct expansion AC systems. It is commonly used to replace R-12 in stationary, commercial, and residential applications because it works with existing mineral oil.