Freon™ MP66 (R-401B) Refrigerant

A Safe, Effective Retrofit for R-500 and R-12 Systems

Freon™ MP66 (R-401B) refrigerant is a hydrochlorofluorocarbon (HCFC) option recommended for retrofitting existing R-500 systems. Freon™ MP66 also works well in R-12 systems operating at low evaporator temperatures (below -26 °C/-15 °F) and requiring higher capacity. These systems include domestic and commercial freezers, as well as transport refrigeration.

Features and Benefits

Retrofitting R-12 and R-500 systems with Freon™ MP66—a nonflammable alternative with an ASHRAE A1 safety classification—allows existing equipment to continue operating safely and efficiently for its lifetime.

While Freon™ MP66 works with existing mineral oil (MO) in many unitary and close-coupled systems, original equipment manufacturers (OEMs) recommend using alkylbenzene (AB) oil for optimum oil return. One compressor oil change to AB typically removes 50-80% of the existing MO, satisfying recommendations and requirements of compressor manufacturers. Additionally, systems retrofitted to Freon™ MP66 need 10-25% less refrigerant.

Regulations on the long-term use of refrigerants vary by region and application, and may change over time. For the latest information, please visit the Regulations page.

For a low GWP alternative, consider the portfolio of Opteon™ refrigerants by Chemours.