Abstract: An economical method for converting a compression type refrigeration system designed for the use of R-12 refrigerant, comprising an evaporator, a compressor rated for R-12, a condenser, and a receiver, to the use of R-22 refrigerant without replacing the compressor or other major pieces of equipment. The retrofit comprises the installation of a pressure regulator in the suction line to the compressor and the balancing of the regulator to the operating limitations of the compressor motor; the installation of a line into the body of the compressor sufficient to inject liquid refrigerant into the compressor for cooling purposes; and the attachment of a desuperheating control to the refrigerant injection line to control the amount of refrigerant injected based upon the temperature inside the compressor. In many embodiments it is also advisable to install a pressure regulator at the outlet of the evaporator to maintain design temperature in the evaporator.