Trouble with Temp Control

[Dan]

Tony suggested that I start a forum thread on my problem so here goes.

The last two smokes I have been having trouble with getting the temp up. With the Auber set at 247 and the smoker set to 250 I couldn't get to 235 on the Auber temp sensor. My Thermoworks thermocouple agreed with the Auber.
On the next smoke, I set the Auber to 225 and the smoker set at 250. I watched the Auber temp go up to 216 and then drop to 208 with the out light on the Auber on and the light on the smoker off. After a while the light on the smoker came back on. As a test, I turned the smoker temp knob down slowly. The smoker clicked when I passed 240 and the smoker light went out. The Auber temp read 208. The temp sensor in the smoker is clean.

Here is more trouble shooting:

1. Yes, The temp knob was all the way up.
2. I just ran the smoker without the Auber and with the temp knob set to full, 250. For a load I put a pan of water on the bottom shelf. I recorded temps with two thermocouple junctions inside. One was hanging about 2 inches from the ceiling and the other was about 6 inches from the ceiling of the smoker. I didn't keep track of which sensor was which.  The graph from the thermocouple recorder is posted as an attachment. Here is what I see on the graph. 
It looks like the on-board temp controller kicks out at about 250 but does not kick back in until the temp drops to about 220. If I have the Auber in series with the on-board controller and the Auber set at a temp above 220, I can get into a situation where the Auber is calling for power and the on-board controller is switched off. That must really confuse the logic in the Auber.
3. I am using a drop in Auber probe.
4. I drop and fasten the probe so that it is just above the meat but not touching it.
5. Before my first smoke, I auto tuned with a pan of wet sand for a load. I dropped the temp sensor to a place just to the side of the load.

I suppose I could bypass the on-board controller but then the smoker is not safe to plug in if the Auber is not in the circuit.

 

[WeekendWarrior]

Will the knob turn past 250?

I would test it with the knob maxed out.  If it won't hit at least 265 with the knob maxed or averages less than 250, I would think the controller is bad.

You could do a toggle switch bypass to allow you to use the auber, or toggle the built in controller back on.

My #2 was averaging about 10 degrees less that indicated, but I was able to do the "knob adjustment" and move the knob to where it shows accurately now.

 

[GeeBee]

Will the knob turn past 250?

I would test it with the knob maxed out.  If it won't hit at least 265 with the knob maxed or averages less than 250, I would think the controller is bad.

I don't agree with this statement. I think the built in controller is acting just like it's supposed to. It's an inaccurate, analog controller. It gets you in the ballpark.

You could do a toggle switch bypass to allow you to use the auber, or toggle the built in controller back on.

I think this is the best solution for you. I don't understand your statement about the smoker being unsafe if the Auber is not in the circuit. The statement is correct, but the simple solution is............don't do it.

 

[Dan]

In reply to weekendwarrior, I have investigated too many fires where someone has bypassed a high temp controller. I can't guarantee that I will be the only person to plug in the smoker. With the smoker temp controller missing and the Auber in the closet out of the weather, I have a fire waiting to happen.

 

[NDKoze]

So, then do the toggle bypass then.

http://smokinitforums.com/index.php?topic=1287.0

You could use a switch like this that would help prevent accidental switching:

http://www.amazon.com/Aircraft-Carbon-Automotive-Toggle-Illuminated/dp/B0061GQUS8/ref=sr_1_2?s=electronics&ie=UTF8&qid=1409234614&sr=1-2&keywords=toggle+switch

 

[WeekendWarrior]

If he is setting the temp to 250, and he's only getting 225 then it isn't working as it should.  That's why I was asking if it would go past 250.

If he turns the dial to MAX and he still doesn't get close to a 250 average then I think the controller is bad.

If he turns the dial to MAX and it does average 250 or better, then the know just needs to be "calibrated" to point to the correct temperate.

I somewhat agree that I would be afraid to do a bypass without some sort of safety feature to shut off power in case of an auber malfunction.  I would hope the auber would fail to OFF instead of ON, but I don't own one.

 

[DiggingDogFarm]

Sounds like heat is being funneled over the stock sensor in some way causing the element to turn off prematurely. I've reproduced that same situation several times during my testing.
If you place a thermocouple as close to the stock sensor as possible, it should help confirm that that is what's happening.

 

[DivotMaker]

Dan, I agree with Martin.  You should place a temp probe as close as possible to the factory probe to confirm its reading.  I would also recommend the switched bypass.

Another way you can eliminate the safety issue of plugging the smoker into the wall without the Auber in place is to change the plug to one that does not fit a standard outlet.  You can then use an adapter to plug it into the Auber.  No chance of anyone accidentally putting it in a wall socket!

I have no use for the stock controller, and have been using the bypassed #2 for about 7 months with no problems whatsoever.  You can't make everything idiot-proof, but you can take the steps above.  At my house, no one touches my smoker but me, and there's no way I would accidentally plug it in...but that's just my situation.

 

[Dan]

Well I installed a bypass with a red guarded switch. I'm still thinking about a more fail safe design. Maybe there is a PID controlled relay out there.
Another thing I learned from my testing is the temperature inside the smoker varies a lot from place to place. Since the art of getting the meat done just the way you like it has a lot to do with variations in temperature and time, from now on I am going to clip the PID temp sensor in the same place every time and then adjust the cooking program.

 

[DivotMaker]

Well I installed a bypass with a red guarded switch. I'm still thinking about a more fail safe design. Maybe there is a PID controlled relay out there.
Another thing I learned from my testing is the temperature inside the smoker varies a lot from place to place. Since the art of getting the meat done just the way you like it has a lot to do with variations in temperature and time, from now on I am going to clip the PID temp sensor in the same place every time and then adjust the cooking program.

Dan, if you run your autotune like that, you should have pretty consistent results.  If you want it to be exact, every time, go for the wall-mount probe...crazy accurate!

 

[Dan]

Thanks Divotmaker,
I agree that the wall mount should help get consistent results. With the wall mount, the temp sensor is always in the same location. Now I have to work on determining my favorite temp and time profiles.

 

[jpittssr]

Tony suggested that I start a forum thread on my problem so here goes.

I suppose I could bypass the on-board controller but then the smoker is not safe to plug in if the Auber is not in the circuit.

I bypassed mine but I have the same concerns. If someone plugs the smoker in it will not cut off until something fails.
I am think about putting some type of plug on the smoker that will not plug into any AC receptacle then make up a short adapter to go to the Auber. Or change the plug on the Auber. Only thing is, I don't know how to remove the case from the Auber.

 

[bigbassnutt]

I store my auber on the shelf below the smoker, this is where its at when I use it and I keep it in the garage so I don't unplug the smoker from the auber so no chance of plugging it in wrong. I am also the only one that uses it so that helps too. If you have multiple people using your smoker then I think the unique plug idea is a good one, the toggle switch is only good if they know what they are doing and if they did know what they were doing they wouldn't plug it directly in.