Hello! I bought this air conditioning service unit used. The seller apparently didn’t really know how to do it. Now I wanted to ask if anyone has any idea of this device or maybe could give me a user manual. Recycling works. Vacuum also. Filling too. Where I have thought about the oil filling. There is a plastic container on the side where the new oil is in but as soon as I open the lock tap no matter if vacuum or fill it whistles out of the container. Think there’s an exact procedure to operate or it’s broken. Hope you can help me