Pit Boss Vertical smoker heat runaway

[ajkey24]

I've been using my Pit Boss vertical smoker for several years now and all has been perfect. I love it.
BUT, day before yesterday, I smoked 2 turkeys and about 9 hours into it, the heat ran away. Instead of holding at 250, it jumped to almost 400.
Then today, after I made sure the temperature probe was clean, I put my prime rib in and it did great for 8 hours before the temp sky rocketed again.
I was able to catch it in time before it turned my roast into charcoal, but even after turning the smoker off and then turning it back on, it is somehow stuck in high temp mode.
Any thoughts on what the issue might be. There is no way to adjust the "P" value so I'm figuring it has something to do with the temperature sensor.
Help please.

 

[BGKYSmoker]

Had the same problem Your temp probe is going bad

 

[bill1]

How do you know it was 400F? The pit boss internal sensor told you that on the PB display? Or you had a 2nd internal thermometer you trust that said 400? If the PB sensor is telling you 400F (and you believe it) then it's hard to argue there's something wrong with the PB sensor...sounds like a control system issue. I assume this is in cook mode, not smoke mode? Had you just completed a fairly long (>20-minute) smoke mode? Then the crucible might have been pretty full of pellets and once they start burning, its hard to slow that train down. If so, I'd say don't bother with Smoke Mode after 4 hours into a cook.

On start-up, these pellet machines can be all over the map temp-wise, but after an hour or so, they're pretty good. And yet you were 8 and 9 hours into the cook! The PB verticals have the control electronics down low, pretty close to the cook chamber. Can anyone comment if the electronics could be starting to over-heat that long into the cook? I know PB has a heat shield you install that helps drop the temp the control electronics see. Maybe loosely wrap some aluminum foil on the side of that heat shield that "sees" the heat. That would be a bit like adding a 2nd heat shield and should help if overheating is the issue here.

 

[flatbroke]

I had a similar problem I got rid of it. Sorry yours is not working correctly

 

[ajkey24]

Had the same problem Your temp probe is going bad

That's what I was thinking. Thanks

 

[ajkey24]

How do you know it was 400F? The pit boss internal sensor told you that on the PB display? Or you had a 2nd internal thermometer you trust that said 400? If the PB sensor is telling you 400F (and you believe it) then it's hard to argue there's something wrong with the PB sensor...sounds like a control system issue. I assume this is in cook mode, not smoke mode? Had you just completed a fairly long (>20-minute) smoke mode? Then the crucible might have been pretty full of pellets and once they start burning, its hard to slow that train down. If so, I'd say don't bother with Smoke Mode after 4 hours into a cook.

On start-up, these pellet machines can be all over the map temp-wise, but after an hour or so, they're pretty good. And yet you were 8 and 9 hours into the cook! The PB verticals have the control electronics down low, pretty close to the cook chamber. Can anyone comment if the electronics could be starting to over-heat that long into the cook? I know PB has a heat shield you install that helps drop the temp the control electronics see. Maybe loosely wrap some aluminum foil on the side of that heat shield that "sees" the heat. That would be a bit like adding a 2nd heat shield and should help if overheating is the issue here.

This thing has alwasy been consistent. I use it several times a month and have never had an issue like this before this past week. I clean the internal temperature probe every time. Even on long smokes like brisket, its gone 15 -17 hours without a problem.
I had a second thermometer in the smoker since I couldn't trust it after the incident with the turkeys two days before. I also noticed it was not pausing. It just kept pouring the pellets to the burner and blowing like a torch.
I'll look at the heat shield, but I think I am going to see about replacing the electronics board and temperature probe. I'm not sure how long it will take to get new ones. If too long, it could be a crisis. I love this thing and we do ribs, chicken or prawns at least once a week on it.
Thanks

 

[Khrakk]

I've had that happen to me twice after a previously really long smoke. I vacuum out my smoker (including the fire pot), and I have not had that problem since. I've had mine for 6 months now and it is typically very stable.

Good luck.

 

[Khrakk]

I should add that both times I had the run away temp was when I was smoking at really low temperatures and after a previous really long smoke. Probably not applicable in your case.

 

[doughboysigep]

mine has done that from day one. got me worried at first but after using it more and more (and not having any issues with what I was cooking) I just chalked it up to "that's how they work". Figured the fluctuations are due to the influx of pellets heating up. temps spike high but only briefly then temp levels out. Again, never had an issues with the results.

 

[bill1]

I've had that happen to me twice after a previously really long smoke...

We normally associate grease fires with very dramatic, meat-ruining events. But any time even just a small amount of accumulated grease/fat is burning at the bottom of your pellet machine, it's a heat source separate from your pellets so stopping the auger (which is all the controller knows how to do) doesn't reduce the temp rise. If this is happening well into a long cook, I think the possibility that a partial failure in your grease control methods (sloped pans leading to channels guiding to buckets or pull-out trays) is a real possibility. I find it's easy to place meat too close to the back or front walls where the drippings can miss the sloped grease catcher pan and potentially start a small fire or heat source down low that may not be "dramatic" but would "confuse" the controller.

Funny how a newer, bigger cooker is the solution to so many of life's problems!

 

[Khrakk]

I agree bigger cooker is the solution to some of life's problems.

My issue was not with grease. I always use a crisping pan underneath what is cooking, so every single bit of grease is caught in the crisper. The crispers go in dishwasher afterwards. There is no grease anywhere near my fire pot, just ash from the pellet. Interesting thing, I bought the crisping pans thinking they would hinder some of the airflow through the smoker and allow the smoke to linger more on the meat. It didnt work well with the airflow, but it does a great job with the drippings. I noted that Bear always uses a pan, so figured I was doing something right.

I was speculating that I had ash build up in the pot from my previous long smoke, and when smoking at a really low temperature, my pellets would burn out while the auger is still feeding pellets. When the temperature drops, igniter comes on and lights a full pot. I watched the temperture rise from 160 over 400 degrees when this happened. Since I now vacuum out my smoker after a long smoke (obviously when cool), I have not had this issue again.

 

[Khrakk]

Here is a roast on the smoker with the crisping pan. I usually use two pans to set up a labyrinth where the smoke is channeled across the meat. Like I said, sounded good in theory, but provided negligible results. Grease cleanup is fantastic though. The roast was excellent, by the way .

 

[bill1]

...use two pans to set up a labyrinth...

I think the labyrinth you want is a plane sheet that reaches tight to all 4 walls with a 1" hole in the middle placed an inch under the grate holding your meat and the exact same thing placed an inch above the top of your meat. Then all the smoke is forced to enter directly under your meat, spread radially around the lower sides, then flow radially inward along the top surface of the meat and go out the only hole directly above the meat.

All the juices will then flow out that lower center hole so place a small catch pan on a lower grate 2-4 inches under the lower smoke baffle plate.