heating issues

[DivotMaker]

Glad to hear that, Rick!  Hope all turns out well.

[cwshiles]

Rick,
Let us know what you come up with. I am having a similar issue and it's driving me crazy. I desperately want to love my smoker, but I can't seem to finish a cook with it. My temps just stall and hold.  Even with allowing for additional hours of time I am still not able to finish. My buddy has a commercial cookshack and I think what I need is a digital controller. I have been trying several cooks to try and hit a home run, but just can't seem to finish a cook. 

I currently have 2 8 lb. butts on my #3 and it's been 17 hours and I am still sitting at about 180 IT.

[Three Sons BBQ]

I have been running some tests since I am new to SI. NOTE also dealing with different cuts of meat as I bought a half pig versus my normal trips to the butcher to get exactly what I want. 

That said... Try an over sized cookie sheet with a 1" lip.  I have and old one and I when filled with water it adds moisture and acts as a drip pan too. And with such a thin amount of water say 1/2" or so it helps act as a heat sink to stabilize the heat your food sees without being obtrusive to the process.

I have auto tuned my Auber and SI3 with this in place and it's rocking holding within plus minus degree F.

Steve

[DivotMaker]

will do on the no pan, since it seems I will have to make ribs this weekend any way 

I've been thinking about the pan on the lower shelf issue, and have theorized that the pan doesn't so much "block" the heat, but rather channels it.  As the heat rises from the smoke box, it is redirected around the edges of the pan.  So, you're actually "channeling" the heat right up the back to the thermocouple.  This would be a "focused" stream of hot air moving across the thermocouple, which would fool it into thinking the box temp is much higher than it is, and would shut the element off before it should.

I'm no engineer, but that's my simple theory!  Of course, I could be wrong...

[sts3d]

I think you should check your outlet and or extension cord if using one. I had a similar issue with a cheap electric smoker a while back. Took a couple of incidents and my Fluke volt meter to figure out that I  had voltage drop of 12 to 30 volts!!!! Depending on which side of the outlet I used. One of the wires to the outlet had loosened a little causing the problem. I found the problem only after the controller melted down from low voltage ,I replaced the outlet and been good since.

[Three Sons BBQ]

... volume too low and air flow minimal for that to be of any significance (re: bottom shelf cookie sheet)... from a heat transfer analysis air flow negligible and there is no medium to transfer any heat except the outlet vent ... Once system stable what you say makes sense but it would be in the 0.01 deg F kind of range.

[rickne]

I think you should check your outlet and or extension cord if using one. I had a similar issue with a cheap electric smoker a while back. Took a couple of incidents and my Fluke volt meter to figure out that I  had voltage drop of 12 to 30 volts!!!! Depending on which side of the outlet I used. One of the wires to the outlet had loosened a little causing the problem. I found the problem only after the controller melted down from low voltage ,I replaced the outlet and been good since.

Possible, but I never used an extension cord and ran this on 3 different outlets/breakers with the same result.  I could have a voltage drop in the house, but I don't think it was the issue.

... volume too low and air flow minimal for that to be of any significance (re: bottom shelf cookie sheet)... from a heat transfer analysis air flow negligible and there is no medium to transfer any heat except the outlet vent ... Once system stable what you say makes sense but it would be in the 0.01 deg F kind of range.

From my experience, placement of the thermometer has everything to do with numbers you register.  I would have agreed with your statement but I've ran this thing several times with different size loads, with two probes monitoring temps.  There is a significant difference in heat between the probe below the meat and the probe above the meat.  It's not such a big deal if you are cooking one thing, but if you have 2-3 things on different racks, it is.

Every smoker I've owned measures cooking temps in the middle of the cooker or higher. 

I've gone with an Auber now and I love my set up.  I can place the probe on the rack I'm cooking on so I can be confident of the temp at the meat level.  It's also given me the flexibility to cook at a wide variety of temperatures.  I can cook pork low and slow, bumping up temps at the end to complete it.  I can cook turkeys at 250 degrees or higher.  I even cooked my beef tenderloin at 300 degrees. 

I'm really happy with this combo. 

SI #3     +     Auber   =   An incredibly flexible, cold weather cooking machine.

[Three Sons BBQ]

... agree if place the temp probe closer to the heater it reads a higher temp.... was only commenting the water pan doesn't impact temps or temp gradients in the box once equilibrium reached. ;-)


QUESTION: Did you bypass the thermostat on your SI3? I am considering doing that and wondering pros/cons? For now I'm leaving it in the loop... sort of like a "safety" on a piece of weaponry... does it get better results of the AUBER?

Steve

[rickne]

Sent you a PM regarding the bypass, Steve.

As far as the water pan, maybe once the box has reached an equilibrium.  But my personal experience has been with a dozen pounds or more of cold meat above a large enough pan, it took a long long long time for my #3 to reach that equilibrium.  I suspect the smaller box of the #1 or #2 might reach that point much quicker (less volume and less meat).

If it's working for folks, don't change it.  It's part of the fun of BBQing.  There aren't always right and wrong answers...   just answers.

[Three Sons BBQ]

Saw the PM. Thanks. I might bypass but thus far I'm staying under 250 so the S13 set at 250  and Auber programmed to 225.... I have effectively bypassed the controller.  Should I want to go above the 250 mark I may need bypass.

Love the response.... There are only answers.. No right or wrong just answers.  How true it doesn't matter as long as the food is good.

[DivotMaker]

... volume too low and air flow minimal for that to be of any significance (re: bottom shelf cookie sheet)... from a heat transfer analysis air flow negligible and there is no medium to transfer any heat except the outlet vent ... Once system stable what you say makes sense but it would be in the 0.01 deg F kind of range.

This is a great theoretical explanation, and makes perfect sense.  But, the historical reality doesn't seem to support the theory.  If you read about this issue not only here, but on other forums as well, the consensus seems to support not using a large pan below the meat.  I'm not sure what the technical explanation is, but many times it has been the culprit that seems to have caused the heating issues.  Not throwing darts - just lending to the healthy discussion!  Like Rick said so well - there are no right or wrong answers, just answers!

[benjammn]

I think that an overall "just big enough pan" would help with the heat exchange issues that are being explained. If the aluminum pan is just big enough to slightly cover the element house, then it shouldn't effect the heat that much. If it is really big, then yes, it will block the heat a bit. But again, if the internal temp reaches the set point, then there is really no "flow" inside other than the extremely small bottom hole and the vent at the top. This wouldn't create enough eddy currents to cause bad readings. This might just be my opinion but seems pretty logical.

[DivotMaker]

Good point, Ben!  One thing that's overlooked, I think, is the "Venturi" effect.  That is, the flow through a smaller hole is greater than a larger hole, if the amount of air passing through both is the same.  If you see smoke flowing from the top vent hole, the air coming in the small hole in the bottom has to be somewhat equal, which would make it flow faster.  So, we really don't know what is going on inside the box, from an airflow perspective.  I would think that the heat of the smoke box is drawing the air in through the bottom at a much higher rate than the air blowing out the top hole, so the lower part of the smoker probably has higher air currents than at the top, where it's diffused. 

[benjammn]

True but with this rectangular enclosure with the intake just below the heat box, then the air would hit that surface and have to mitigate to other areas after hitting it. Thus it wouldn't be a perfect flow. God I wish I had that particle software to make a graphic of how the flow would work inside these units. Can Ben or Steve make that?

[digger1978]

Could you add a bigger heating element?  Would that increase the temperature?