Good day friendship, Emphasizing what the friend TECNI2016 commented: 1.- the equipment must be completely clean, 2.- you must observe in detail if there is oil in the pipes (it is a sign of leakage) 3.- you must measure the working pressures, Low and High, For this you must have at least one set of manometers and two valves puncture tubes since surely the window equipment must not have installed service valves (this case is in case there is no leakage present (OIL SPOTS). Once you have those tools, upload a photo to indicate where you should place the valves. Do not forget to rate me. 8-)