OK - I came home today and took off my two risers. Put the ball valves on the pipe nipples on the bottom of the drum ( 3 of 'em) and lit it up. I've not been able to get past 210, but right now, with only about 1/3 of a basket of old lump, my drum is humming along at 260. My exhaust holes are equally spaced around the outside of the lid (5 - 3/4" holes), and the outside thermometer is reading 260 and the inside one, in the middle of the grate is reading 270. I'll cook on it this weekend (new WSM won't be here yet) on see how the temps do then. For now, lower is better!

Jack2u2,

Keep us posted. Really want to hear the results. Thanks.

Well, sorry for taking so long to update my own post... On the second UDS I built, I put 2 1" intake 'nipples' with ball valves on the bottom of the barrel and left off the upright pipe... I have 4 1" exhausts on top. This is the way I will do it again. Works like a champ. Easy and consistent temp control.

I took the pipe off the 1st one and same results.

The other thing that I had problems with on the first was the thermo on the side of the drum was erratic. At first I chalked it up to being a cheap $10 thermo... It was mounted almost directly above one of the intakes on the bottom... Second UDS I put it 90° from the two intakes and it reads correctly... So don't mount your thermo directly above an intake!

lessons learned...

James.