Both the SmokinTex and the SMOKIN-IT models suffer from a lack of oxygen and have trouble using the AMNPS. I have been working with Todd for a couple of years to find a remedy for this problem and after some test runs I think we have found an easy solution.
As you can see - both look identical inside ( sorry about the different size pics - these came from their websites) and both function basically the same. Normally you add chips/chunks to the box in the center bottom to generate smoke. There is a heating coil that is covered by the smoke box (see mod pic for details)
Due to the fact that both are very well sealed, the only airflow is from the drain hole under the smoker box or from the vent on the top of the unit, there is not enough airflow to keep the AMNPS going when hot smoking. I have had great success with the AMNS in my SmokinTex but the SMOKIN-IT users report that they are not able to use either the AMNS or AMNPS with any success.
My first test was to raise the entire smoker up off the drip pan and that worked great for the AMNS for both hot and cold smokes as it allowed more airflow under the smoker in into the smoker thru the drip hole.
My next mod was using a small aquarium pump with a copper barb up thru the drip hole which had minimal success and cause some heat issues.
I tried adding a fan on the side of the smoker with a baffle near the drip hole to force air up into the unit which also met with minimal success. Some days it worked well and some not at all.
I started enlarging the drip hole and started to see more progress as I enlarged the hole. At 3/4" I was almost there and was looking at going to 1" to see if that worked. I did not have a 1" even with my step drill bit so Todd and I decided to try a second hole since the drip pan is 10" long and both holes would drip into the pan. This has solved the problem and is working very well. I have run the unit several times with great success and complete burn thru on the pellets.
Here are some pics of the mod - very simple and cost free.
I drilled the second hole directly behind the first (original) drip hole right below the box. This pic shows the heating element directly above the holes
This picture shows the whole floor of the smoker. When I am actually smoking I cover the entire floor with foil and poke a hole in the foil for the drain hole. This helps with clean up - I also cover the top of the smoke box in foil as well. Sorry for the fuzzy iPhone camera work
Here is the AMNPS getting ready to go into the smoker - look at that beautiful TBS
Here is my configuration for the AMNPS in the smoker - this allows me to cover a small area of the bottom rack to protect the AMNPS from dripping meat
You can see the TBS coming out the vent hole. Success at last !!
Hope this thread helps other SmokinTex and SMOKIN-IT users with a plan to use the AMNPS
Send me a PM if you have any questions