Temperature problems with UDS

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jdowning

Newbie
Original poster
Oct 10, 2013
1
10
I've built a couple UDS's now and I'm having the same problem with both.  When i first start out I have to light at minimum a chimney full of briquettes, sometimes even more just to get it up to around 250 degrees.  I see others on forums and videos that only have to light around 10 briquettes to get it up to temperature.  I have 3 3/4 intakes with 2 ball valves.  I'm cooking a brisket as I write this and with a chimney and a half of lit coals on the top I have to have all intakes wide open to keep the temp up and it still seems to be slowly dropping.  My basket on the one I'm cooking on now is 15 inches in diameter and a foot high wall made of 3/4" expanded metal.  It's about 2 inches off the bottom of the ash catcher.  I have had several good cooks on the UDS but seem to always have this issue in the beginning.  Any advice would be greatly appreciated.  
 
I've only used mine about 5 times , but i think getting the fire real hot first and then closeing vents off has worked better . good luck.
 
Ball valves really restrict air flow, I would remove one and just go with 2 3/4 intakes plus one ball valve.  Also, I find that any breeze at all really drops the temp on mine so I usually use a wind screen (3 pieces of used plywood to butt up against the shed I have the UDS next to) which helps.  I also use a 3"  stove pipe elbow as a flue.  One nice thing about a UDS is it's cheap and you can modify till you get it the way you want.  Keep trying, you'll get it.
 
To troubleshoot, how much charcoal are you consuming? If the charcoal lasts a long time and you are not getting to temp it seems it would be airflow. If you are going through charcaol like crazy (or any fuel for that matter) and not getting to temp you have a heat loss (sink) issue.
 
j, evening.....   we need pictures to see how the inlets are placed etc.....   and try raising the basket up with 4" bolts, double nuts and washers...   And a picture of what you have for an exhaust....    We are guessing at what you have going.....  By chance, are you using a water pan with water in it..???

Dave
 
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  I see this is your first post. Will you drop by roll call so everyone can give you a proper SMF welcome.

Also if you would add your location to your profile it ould help us know what temp and altatude your at as well as othe usefull info.

Now to your heat issue I would be grat if you would upload a pic of your UDS. 3 3/4" holes should be plenty of air. What kind of opening do you have for a chimmey do you have. You have an air flow problem. I can get mine above 350° with ease. What brand of charcoal are you using? is it burning fast or slow? Starting with a lot buring is not a problem as long as you don't get it to hot and start chasing the temp. Are you using a water pan? how much food in in the UDS?

Happy smoken.

David
 
Thats a boat load of lit coals.  I only use 15 pieces  to get it going.

I have  ( 2 ) 1 inch nipples and  ( 2 ) 3/4 ball valves.

What do you have for exhaust?

I would say not enough air flow.

UDS's would with good air flow in and out.
 
When I built mine, I put 3 1"-holes 3" off the bottom edge of the barrel.  1 has a ball valve, the other two are capped.  I have no problems getting mine up to 400° if needed..which i don't.  But I do let the temp run up to 350 or so then back it down to the required temp before I put the meat in it. 

I've found that how I build my fire has a lot to do with it also.  If I fill the basket with coals and just dump the lit briquettes on top, I get a hotter fire.  If I hollow out the middle of the basket and dump all the lit coals in the middle, i get a lower temp, but more consistent burn.
 
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I have only two holes, each with a 3/4 ball valve. During my seasoning burn I had both wide open and temps were rock solid at about 305 (mounted thermometer) I've found my lower grate temps are about 30 hotter. I have no need at the moment for higher temps so I plan on leaving mine as is. I have the hardware to add another if I wanted to cook hotter. My charcoal basket is 17 or 18" Weber charcoal grate with 8" high expanded metal. I have 3" legs attached to an ash pan that has a 1.5 to 2 " lip.  You can see pics of my rig here http://www.smokingmeatforums.com/t/150304/my-uds-build-and-first-use-two-chuck-roasts if that helps. Pictures of your setup might help us figure out the issue.
 
I am not a long time veteran of the UDS build, yet.  As I am writing this I am seasoning mine so I can cook on it on Saturday.  I have a different design than you so I am not sure if it matters or not.  I have four valves in the bottom of mine.  I used three 3/4 pipe nipples and had them welded in.  The fourth nipple I attached a water spigot on it.  It does not have any rubber parts in it, just all good american steel.  So I started mine by uncapping the three nipples and opening up the water spigot wide open.  I use the Minion method and light about 20 or so briquets in my weber chimney starter.  Then once they are all white add them into the basket and put it in my drum.  I left the lid partially slid over to the side until my temps hit about 375...then i let it cook (I needed to season it) for 2-3 hours.  After 3 hours or so I put on 2 caps and left the spigot wide open and one nipple uncapped.  It went down to 300 degrees.  Then I put on the other cap and it is perfectly sitting at 250.  I am sure i can adjust the spigot as needed.  I have been real careful to make sure everything is sealed up real nice.  I also used some wood chunks in with my charcoal.  That is what I have done.  Just thought I would share...hope all is fixed for you!
 
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First post here - if you don't think the airflow through the drum is a problem, it may be the space between your ash catcher and the height of the bottom of your basket (different air flow problem).  My basket is about 5.5 - 6" from the ash catcher, and the air inflow is ~3/4 " from the bottom of the drum....I cant remember exactly.  Though I did not order a Big Poppa Smoker Kit, I did follow the dimensions they used, as it was my first time to build (i.e., height of holes, basket, etc.).
 
Tonight i lit about 3 coals....short time later it was over 400*( ran a temp test) and it was 8 degrees wind chill outside.

It's a mix of enough intake AND exhaust.   It's just important to have adequate exhaust.   Take Cfarmers advice on the inlets.  Keith
 
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