UDS Temp Control

Midnight Smoke · Feb 1, 2008

I built my UDS using 2- 3/4 intake ball valves and using a 8" pipe in the 2" top bung for the exhaust. Built a 15"x10"h fire grate sitting 2 & 1/2" from the bottom, the cooking grill is about 24" from bottom of fire grate. Read a bunch of threads and cannot get the temp to stay even at 225º.

I put about 10lbs of K in the basket used a 3lb coffee can in the center and dumped in about 3/4 Weber of lit charcoal and put the lid on (removed the coffee can). I adjust the ball valves at 1/2 hour intervals and cannot get it right either running too hot or to low. I read where most of you set it and forget it for hours at a time.

When I dump the lit charcoal in how long should I leave the lid off, am I closing it too soon before the fire gets going good?

Should I try drilling 6-8 1/2" holes in lid and just block the bung holes, I am thiking maybe not enough airflow?

What am I doing wrong?

chinesebob · Feb 1, 2008

Do you have some pics of the fire basket in the barrel?

I wait until mine are white hot to dump in and I don't use a coffee can. I clear an area in the middle. Not sure what to tell you.

Meat Burner · Feb 1, 2008

Pork, sounds like you are doing everything about right, except the lid thing. Open your intakes full and keep the lid on from the get go. When temp gets to your target start closing the intakes down to stablize the temp. My drums come to temp in maybe 20+ minutes but don't really get stable for about 45+ minutes. It takes a little while to get the unlit fuel going smooth. Just experiment and you will get it dialed in. Remember, adjustments take time on a UDS. Someone will chime in here but the 8" exhaust may be too high to draft correctly. Not sure about that at all. Hope this helps. Just my $.02.

Midnight Smoke · Feb 2, 2008

CB, Will try and get a picture of the basket.

MB, Maybe I just need to give it some time to learn the settings. How many intakes do you have?

Thanks for the responses...

Meat Burner · Feb 2, 2008

Pork, I use four 1 /2" intakes....just seems to work for me. Your setup should be fine. Have seen several posts here that use what you have with perfect results. Mine take a while to settle in to an even temp and then stay there. Couple of cooks and you will have it dialed in. Don't leave the lid off, that is what spikes the temps. Getting temps down are tougher that getting the temp up. Keep us posted!

smooookin · Feb 2, 2008

Try taking the 8 in pipe off and just have the 2in open. If you leave the lid off for too long the temps will jump and could give you fits trying to get them back down. The UDS in my avatar has a street L in the bung instead of the 1/2 in holes in the top and cruises just fine, usually with only one valve open. Also you can fine tune the temp control by using the small plug in the top also. If my temps start to climb I will remove the plug which seems to just let the heat escape instead of fanning the flames.

Midnight Smoke · Feb 2, 2008

smooookin said:
The UDS in my avatar has a street L in the bung instead of the 1/2 in holes in the top and cruises just fine, usually with only one valve open.

What is a street L?

Since you use just 1 intake how is your exhaust positioned? What I mean is, is your exhaust on the opposite side of the drum from the intake?

Thanks!

smooookin · Feb 2, 2008

A street L is a 2in elbow with a male end and a female end. The male end screws into the bunghole and the plug screws into the female side of the L.

The position of the L in relation to the valve kinda depends on which way the win is blowing. I have never really paid that much attention to it to be hones but I do know I can adjust the temps by turning the lid.

Bbq Bubba · Feb 2, 2008

Hey Pork, How tite is your unit? Any air at all will wreak havock with the temp. I use 1 ball valve and 1 nipple with the cap off, do all the adjustment's with the valve, my drum won't hold at 225 but will stay all day at 238 so that's what i look for! I have used the 2" bung for exhaust with a riser and without, seem's to draw better with but maybe draw's to hard!
Next time make a hole in the center of your charcoal and only lite about 20 briquette's in your chimney, dump those in when their hot, put your meat on and close the lid immediately, leave 1 valve open and start adj. with the other when it come's up to temp!!
Good luck, patience and you will be rewarded! :wink:

Crüe-B-Cüe · Feb 2, 2008

The first one I did held between 230 to 240 just fine. The second one I built on the initial run went up to 300 - 310. I closed both ball valves and left it for hours. Still holding at 300. So I figure I have to be getting air from somewhere, so it must be the lid. I'm using a kettle lid and I had to grind the rolled lip down on the drum to get it to fit. I think I need to grind it down a little more so the lid will go down a little further. Don't give up, you'll get there.

Smokin Gator · Feb 2, 2008

There seem to be several things that have caused people problems until the got them figured out. Obviously the air that is drawn in. It sounds like yours should be fine. I would suggest as others did that you make small adjustments and give it a chance to setting in. Another is the exhaust. I don't have any direct experience with a set up like yours. One of mine I use a Weber lid and just have for 4 holes open all the time. My other one has four 1/2 inch holes spaced evenly around and toward the outside of the flat drum lid. Again though, yours seems fine as others are using a similar setup.

The one thing that some have had trouble with that my be giving you problems is the size of the fire ring. I think it was Keale who had fits with this with a ring that was similar in size to yours (if I remember correctly). Mine ring is about 18 inches in diameter and about 5-6 inches high. I start mine as you said you did yours with the coffee can in the middle. I might be a few briqs short of 3/4 of a chimney. I would say more like a heavy half.

Keep playing with though and see what happens.

Irrad8 · Feb 2, 2008

Pork Smoker- Thanks for asking this, I'm having the same problem.

N8man · Feb 2, 2008

I fired mine up about an hour ago...16 Kingsford briqs lit in chimney, ashed over well, dumped into circular void in center of unlit briqs in fire basket.
Added some wood chunks around perimeter of fire basket, closed lid and opened one intake about a third, temps stabilized @ 235 now. Time for meat...My intake pipe is 1" and my exhaust is a single 2" pipe eight inches long with an elbow, Hope this helps....

keale · Feb 2, 2008

Hey Pork, Aloha...

I did have probs with a too wide fire box... but I believe the main prob. was the exhaust, I had too many holes, (weber clone, w/ slits)...if you don't want to mess with your current exhaust try N8's magnet thingy...or what I do, "tinfoil" mod...or stick a piece of paper to block some of the air... Pics would be helpful, and keep us informed... and yes check your lid for leaks...

Jack2u2 · Feb 2, 2008

He has problems with too hot -- I have problems with not hot enough. I have 3 - 1/2" intakes with ball valves. I have 5 - 3/4" holes on the lid for exhaust. I can run 210 -220 all day long, but I cannot get up beyond that. No 300-350 for chicken. My firebox is 15 3/4 by 15 3/4. Right now I'm cooking at 225 wide open. 14 lbs. of lump since 1:30 am. But. that's it --- no higher!!!!!

smooookin · Feb 2, 2008

Does the lid have the bung holes in it? If so, try removing the smaller one first. If that doesnt work, remove the larger one.

Hurricane Kurt · Feb 2, 2008

Jack2u2 said:
He has problems with too hot -- I have problems with not hot enough. I have 3 - 1/2" intakes with ball valves. I have 5 - 3/4" holes on the lid for exhaust. I can run 210 -220 all day long, but I cannot get up beyond that. No 300-350 for chicken. My firebox is 15 3/4 by 15 3/4. Right now I'm cooking at 225 wide open. 14 lbs. of lump since 1:30 am. But. that's it --- no higher!!!!!

You need more air. I would drill a 1/2'' hole, 1'' up from the bottom of your drum. Then another later if needed for chicken temps.

Kurt

Midnight Smoke · Feb 2, 2008

I am glad to hear there are a few others that maybe having the same problems.

I removed my 90º elbows from my intakes and removed the 8" pipe. Loaded about 12lbs of unlit K added a few chunks of hickory and spread from center of fire box. Dumped in about 3/4 Weber lit.

Elbows removed

The Fire box

Another shot

In the drum, there is about a 3" space all around the fire box to the drum

Another

Ready to go on, 8lb butt. 1st one using the UDS

The start

Will post the progress

wlh3 · Feb 2, 2008

I have a 2" airintake and a 3" X 14" exhaust. Fire box is 7" X 14" 2" off bottom of drum I use a coffee can in middle of briquets. put 5 or 6 briquets on my smokey joe and light them, using tongs i then drop them in to the coffee can dump 10 more unlight birqs on top of them wait 15 minets lid is off and intake wide open. At the end of 15 min. pull the coffee can out put on lid and close intake 1/4 to 1/3 open. Wait another 15 min or so I should be running about 210* to 230 * then wait till smoke settles out. To put meat on I shut intake off for 3 min pull lid load meat put lid on wait 3 more min @ the end of 3 min open intake back to 1/4 or 1/3 open this controls the spike. Bigest lesson learned must have control over ALL air going in to control the temps. Hope this helps:icon_bigsmil

Smokin Gator · Feb 2, 2008

That is a great looking butt ya got there!!! The drum is really nice looking too.

UDS Temp Control

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