I dont know about the vac. It was hooked up to an all in one machine. It recovered what it could. Pulled vac, then injected oil, added freon, all without removing any connections until it was all done.
Think I saw 18" of vac when it was doing it's thing? Not entirely sure though. It was all automated and had little intervention from us. It just beeped at the end of every step so we could push the continue button.
I didn't learn a lot, but I did learn that if I was going to do a lot of AC work, I'd want one of these machines.