A new gas recovery system for the resistive plate chambers (RPCs) at CMS (Compact Muon Solenoid) experiment was installed, commissioned, and tested to find the optimal operating configuration in terms of recovered gas quality and system efficiency. The aim of the system was the R134a recuperation, using a distillation process, to solve both the environmental and the economical issues, considering the high global warming potential, of 1430, and the high specific cost of R134a. The system works with an input mixture composed by 95.2% of R134a (1,1,1,2-Tetrafluoroethane), 4.5% of isobutane (C4H10), and 0.3% of sulfur hexafluoride (SF6). The recovery system was designed in four units: the electric rack, the distillation unit, the pumping unit, and the storage unit.