Last night was the second time I used the auto filler. I too had issues with the shut off as well. The screw on mine was almost falling out at 5" of vac. Wade I believe hit it on the head. Keep your set-up the same every time, (length of hose, locationwhich I believe is the key. This thing still rocks even when I had to finish by manually shutting it off. 22 bottles of Lodi CA Cab Grapes, Filter (5 micron), bottle, and cork, 14 minutes.