if you check out my video on the bender, u can see i dont have a regulator on the vac pump= that vac pump pulls 26 so im guessing i had that or atleast 24-25 at the milk releaser and it still dumped fine, mine has a little weight on the top though not sure if they all do? found out yesterday one of my benders bottom wasy BROKE! going to fix it with a rubber coubling and should be good togo!