Perceived airflow prob on my UDS

[peddler]

OK guys humor me on this post if you will.

Trying to fix a perceived airflow problem on my UDS that was built by Norco's recommended plans back at the first of the thread.

1) I am using a cheap grill pan as an ash pan, I felt the lip on the pan restricted air to the basket so I drilled 24 1" holes around the lip of the pan...this should help air movement under the basket.

2) I had used 3/4 conduit as risers on two of the 3/4 inlets. Got to scratching my bald head and thought that conduit is measured outside and pipe is measured inside so I replaced the risers with 3/4 X 18" black pipe thus increasing the intake air flow. Ball valve (brass) on each riser.

3) Fired up the smoker and ran an experiment on lids. The original has 8 1/2 holes around the perimeter about 2" in. Changed lid out to one that had a 2" bung hole and installed a 2" X 18" pipe riser or stack and appears to have better flow..

4) I am using a 12" turkey thermometer only and reading pit temps by that. Norco's plan uses a thermometer that has a 3" probe and I have read that there could be a 50 degree difference from outside to center ... is it possible that I'm cooking too low if the 3" thermometer (that I don't have) is reading 225* and the center is 50* hotter thus cooking more quicker. (Example outside at 225* as recommended thus the inside at 150* thus too low ???)

Please excuse the micro management of this simple appliance but I was totally not impressed with the brisket that I did last week and trying to get a handle on my problem (If I have one).

Thanks in advance

Jim

(This was also posted on another forum)

 

[coffee_junkie]

I wouldn't assume you have a 50* temp difference. If you can get a longer thermo that would help you figure out what your drum is running at. I run my digital thermo which is approx an 8" probe, I run my drum smoker so that the lower grate is at 250* (ish).

I am confused at your question #4, you ask if you are running the smoker @ 225* (measured at the outside edge of the smoker) would the inside be 150*? (at the center of the smoker). First that is a 75* temperature difference, which I just don't see happening unless you have a baffle above the charcoal grate. I would guess that if you are measuring 225* at the outside of the smoker, it may be 250* (or maybe a bit more) at the center, which is just about perfect.

The best way to know what is going on is to use a couple digital thermometers. But reguardless of what thermo you are using make sure you calabrate your thermos (or check for accuracy) use boiling water (check what water boils at for your elevation) and ice water (should measure 32*)