"I use wood chunks and 1 charcoal briquette (to develope the smoke ring). About 4-8 oz. of wood is all that is needed, and it will put out TBS for a good 5-6 hours. That's usually about 2 half-fist sized chunks."
"I've used this unit at least a dozen times now with no problems, that is until today.
Put a couple racks of ribs in, and some apple and hickory chunks for smoke. The only thing I did diferently is add a water pan. But somehow, when I went to check on things after 30-40 minutes, the temp inside had skyrocketed! I knew what it was before I even opened the door; the wood chunks had caught fire and were burning up! I just don't know why."
"A short update: I added some felt tape gasket along the seal to help close any gaps that may let in more oxygen. Also, because of the large amount of water I had in a pan (about 8 cups), I believe the element was working harder to increase the internal tempurature of the box. I think this, coupled with the added oxygen, is what caused the open fire in my woodbox.
I have successfully done 3 smokes since then, in one of which I used a much smaller pan and volume of water. Works like a charm now.
Live and learn."
I don't think the volume of water was a factor. 4 pounds of water is going to suck up as much heat as 4-6 pounds of meat. If I understand the physics correctly two things are happening.
First you have evaporation drawing some of the heat out of the water. (And that heat is going into the box.) This I believe is a function of the surface area of the water.
Next, the water is absorbing heat until it becomes steam.
Have you given any thought to making the smoke outside of the cabinet and then piping it in? It seems to me that were you to do that you could tightly control the quantity and quality of the smoke and also you might get less condensation of the smoke on the walls of the cabinet making cleaning easier.