A generic procedure, which meets the main steps, would be as follows: (a) cleaning the system with R141B refrigerant; (B) After cleaning, expel R1411B with nitrogen; (C) replacing the mineral oil used in R22 with the polyol ester oil (POE) indicated for R407C; (D) replacing the dryer filter DN by DU for R407C; (E) make the maximum vacuum in the system reaching at least 500 microns; (F) recharge the system with new R407C fluid through the liquid line and R407C in the liquid state; (G) analyze the operation of the equipment by regulating the overheating of the expander so that it is between 6 and 8 ° C.
This procedure would satisfy the retrofit process from R22 to R407C. Our recommendation is to consult the equipment manufacturer or the compressor manufacturer directly for specific retrofit procedures from R22 to R407 or R404A.
