Is my stoker broken?

[Bryan Rabe]

So I have been having the hardest time keeping my temps manageable, and I just figured it was my smoker. I have been modding my smoker, making sure I have no leaks and everything is in order, but to no end I keep fighting it. The kicker is the first ever cook I did on the pit the temps were ROCK SOLID...

Here are some graphs:

First ever cook:

Test last night:

Now let me explain. In my previous tests I found out the smoker overshot 25f on start up so I set the smoker to 225. Once it hit 225, I let it sit a half hour and bumped it to 275. Once that happened madness ensued(this is what I see happen a lot). It overshot the 275 temp and went to about 290. at 290 it shut down the fan and let the pit cool which is all fine here is where it goes whacky...... instead of kicking on the fan when the pit hit 275, it waited until the pit was about 260. When then fan turned on it would then overshoot to the mid 280's and let fall back down to the low 260's...***! Then out of nowhere it fixes itself..

The first few cooks were like the first graph, then out of no where it started with these crazy graphs.. what gives?

The smoker doors where never opened.

There was no wind.

Stoker fan is orientated correctly

Brand new fan (suspected a faulty fan)

 

[Gerd H]

See what the graph looks like in an electric oven.

 

[Steve Cole]

I've had similar experience. Temp on some cooks are very even, but sometimes it's like a yoyo. Throw even a light breeze on the intake side of the fan and temps can spike. I don't think there's problem with the Stoker. I think it's just the random/unpredictable burning of a low fire, with lump anyway. That's why some folks try to stack/pack the charcoal so evenly, that and get as much in as possible. That's my best guess.

BTW, the fan looks like it kicked on around 267-269, but the temp didn't start climbing for a few minutes and bottomed around 265, midway through that fan cycle. By the time the fan turned off, around 275, the fire was apparently burning well and just carried over. Sometimes charcoal just doesn't burn evenly.

 

[Amir]

As noted, it is "normal." Control systems overshoot. If you change the overshoot, then the response gets slower. It is a trade off.

The best thing to do is to play with the damper. I have managed to go from wild oscillations to rock solid doing that. But most of the time I don't care. The long smoke won't be impacted anyway.

BTW, one other factor is the blower size. If it is too big then it will excite the fire too much and that causes stoker to be more cautious and lets the temps drop too far before turning on.

 

[Peter Gallagher]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bryan Rabe:

I let it sit a half hour and bumped it to 275. It overshot the 275 temp and went to about 290. at 290 it shut down the fan and let the pit cool

[pbg]If you had it set at 275 and the fan was running at a temperature > than 275 then there is a problem.

which is all fine here is where it goes whacky...... instead of kicking on the fan when the pit hit 275, it waited until the pit was about 260. When then fan turned on it would then overshoot to the mid 280's and let fall back down to the low 260's...***! Then out of nowhere it fixes itself..

[pbg] What temp was it set at? If you had it 275, and it overshot to 290, then it dropping to 260 before turning back on isn't too weird. Maybe because you had set it at 2 different temps, it took longer to accumulate itself because it never had quite had accumulated itself to the the first 225 setting?

</div></BLOCKQUOTE>

 

[James Harvey]

I used to leave the lid damper at 100%. After a few windy cooks, I go 25%. With that, my temps are pretty stable unless I start with too much lit.

 

[Ryan Reuter]

I agree that the damper is key. Yes it's cool to have it wide open and let the smoke freely flow; also to not feel like you're restricting or choking out your burn along with using your fan less.

You need your smoker to be able to apply the brakes on an overshoot though. With your damper pinched down, it will shut down overshoots promptly and your cook will rely more on your fan.