I'm having a similar problem. When I first got it, all my tanks seemed to work fine (smok pyrex udct, boge f16, davide bdc, aerotank, nautilus). Then, my aerotank stopped making contact. I am aware of the center pin and started adjusting it with a screw driver. I went in small increments till I reached all the way to the top. Still no go on the aero tank, but all the others were still working. Now my boge f16 tank stopped working with it also. I thought maybe it is not making contact with my provari from the bottom, so I pushed the hippo center ring down a bit so that it would protrude from the bottom making a better connection with the provari, and using a screw driver raised the center pin so it can make a better connection with the tank. It's now working again with the Boge F16 (just barely), and still not with the aerotank. To me it seems that even with the center pin raised as far as it will go up without coming off, it's still not high enough.
What about putting some Noalox on the threads?
The only thing I didn't try is tightining it down with a wrench, I'm afraid to do this and end up pushing down my provari pin.
Do I have a defect? Do they need to make a V3 with a higher adjustable center pin? Is it safe to wrench tighten it?
thanks