HCFC-22 is the word’s most widely used refrigerant. It serves in both residential and commercial applications, from small window units to large water chillers, and everything in between. Its particular combination of efficiency, capacity and pressure has made it a popular choice for equipment designers. Nevertheless, it does have some ozone depletion potential (ODP), so international law set forth in the Montreal Protocol and its Copenhagen and Vienna amendments have put HCFC-22 on a phase out schedule. Zeotropic blend HFC-407C has been established as a drop-in alternative for HCFC-22 in the industry. However, when a system is charged with a zeotropic mixture, it raises concerns about temperature glide at two-phase state, differential oil solubility and internal composition shift as well as dilemma associated with the correct charge of the partially leaked systems. The purpose of this study is to investigate behavior of R407C refrigerant in the liquid chiller systems, including performance and efficiency variations as well as challenges involved maintaining the system charged with R407C.