British BBQ Society Forums

Hi all,

I finally built my pit controller the other day and have been trying it out but without much success.

http://s44.photobucket.com/user/essexsm ... t=3&page=1

The first time I used it I put it direct onto the ball valve on my UDS, but the temp kept falling. So, I opened up the other valve and port and hey presto the temp came back up. So, to me that indicated an air supply problem.
Looking inside I could see that the air supply was no where near the coals, so I made a copper frame to deliver the air directly under the fire basket.

I tried that today but with much disappointment the same thing happened. I have removed the frame and put the fan directly onto it to check for air and I can feel an airflow pretty much all the way around. However, obviously there is still an airflow problem.

So, before I go drilling bigger holes and potentially ruin it I wanted to ask what people thought.

The fan is 18cfm or so it says in the spec. From what I've read 10cfm is quite common, so I thought this would be overkill and I could throttle it back with the valve if necessary. The pipe is 15mm, my thinking being that the fan would fill a smaller bore pipe and blow all the way around it. The holes are 2mm, again so that the fan would blow all the way around.

I should say that the coals are in a snake.

So, my question is, has anyone else done this and what size fan and holes did you have?

I have a slightly larger fan but that means a fair amount of rebuild and it wont be half as neat and convenient.

Thanks for your your help!

I've got a 10CFM fan blowing through 2 15mm input pipes, I have about 16 or 17 holes on the copper 'air burner' and the holes are 6mm. I started with less holes that were smaller and had to increase the number and the size of the holes so that I could reach 120C quickly and hold it comfortably without needing the fan on full blast all the time.

Some pictures here https://www.dropbox.com/sc/752f2fyg3n96 ... -agIVwGs0a

I can't see the pictures you put up though.

Thanks Jams, that's great. only just upped the holes to 3mm but was thinking they probably need to be bigger. I have about 5 holes on 3 sides so about 15 total. Will up it to 5mm to start with knowing that I should be fairly safe.

Photo bucket is playing silly buggers again!

With hole size I was worried about the fire being able to draw air through if I made them too big but it doesn't seem to do that. I wanted to be able to drive the temps up above 120C fairly easily if I wanted to, I seem to be able to reach 130C but I'd like to hit 150C so I'm looking at some modifications or maybe a bigger fan.

I've read that you want the fan to run at 40% of the time. Obviously I've still not been able to get mine going properly yet. I've got another bigger fan already to go anyway but didn't want to over Stoke. Though I can throttle back with the valve. How stable are your temps?

temps are solid enough for me to go to bed without worrying, it only really varies when I open up the hatch or take the lid off.

I'm going to try going with foil over sand in the water bowl next, I also want to try and get the fuel burning more evenly which is tricky with lumpwood.

Wow, sounds good! That's what I'm hoping for. Yeah you might struggle with that one. Let me know how it goes.

Try this link instead. https://drive.google.com/folder/d/0B0oX ... x4Tk0/edit

I love your little fan holder, is that 15mm all the way around? My 2x 15mm inlets feed into a 22mm 'square' inside the smoker and as mentioned my holes are a lot bigger. I suppose if I pre-planned enough I could work out total airflow through X holes of Y size given Z throughput but I'm more of a seat-of-the-pants kind of chap

Thanks. You can see why I didn't want to change it. It's really light and neat. I put the wire through the front so that I can turn it upside down if it rains.

Ahh, so the pipe inside is 22mm? Think I need a rebuild.

I did another burn last night and I still had hell with it. I now have the same surface area in holes as you do. It was a very strange burn. With my fan 100% I still needed both ports open to get to temp. I also had to crack the lid a bit to get it to rise. At the end I had a look inside and all the coals had lit but the bit at the start had gone out and was only half burnt.

I have another design in mind so might just go with that.

How long does your unit take to get to temp from the start?

On the bright side I did a brisket and 2 racks of ribs for 3 or 4 hours then finish in the oven. First time I've done brisket and it was amazing. Didnt need a sauce or anything. Mmm.