Back burn through auger tube *Update*

[its a gas]

Update: Camp Chef was on the ball with getting back to me. Very impressed with their customer service. Most of the suggestions where already done. However they did mention auger tube build up of pellet dust and vent to chimney. The dust can ignite. I cycled the feed to remove all pellets in tube. Got my compressor and thoroughly blew out all the dust. Also noticed a build up on the chimney vent slots. This is tough to see without a flash light. Cleaned up that as well.
Seared at 400 for 15 minutes, and so far so good. Will try 500 at some point and re check. Thank you everyone for your input. Much appreciated!




I have a CC DLX24, and decided to reverse sear some pork. Dialed in the temp to hi which peaks at 500* When the meat was done, I dialed in shut down which is 20 minutes. Just before it ended, the hopper started smoking. The unit turned off as should, but it still smoked for about 20 minutes. I took out all the pellets in the hopper for fear they would catch, but it seems the auger tube had some back burning going on.

Traeger pellets are new. Ive also used bear mountain. This is the first time searing, so Im not sure if brand of pellets would cause the same thing,

I stumbled on traegers site, and they mentioned to put in smoke mode four about 20 min before shut down mode.

 

[mike243]

I would run it as low as I could after running it that hot to make sure the burn pot was cooled down enuff that it wont start pellets after shut down, I could see that happing if you opened the lid , my PB will run until it hits a low temp on the thermistor but if you open the lid it wont sense properly and would shut down quicker, which could leave the burn pot hot enuff to fire some off.

 

[retfr8flyr]

Any pellet grill that uses a direct to the firebox feed auger is subject to burn back. You need to let it cool down from high temps before you shut it down. The only way this is avoidable is with a drop design firebox like the Yoder and some others use. I don't really use my 1300 for high temp cooks, so I have never had that problem but it can happen anytime you really crank up the temps, you have a raging fire in the firebox and if you shut it off the auger stops feeding pellets. The fire is going to look for more fuel and start going up the auger tube. Your lucky you caught it when you did, as the pellets in the box could have caught fir also, it has happened many times.

 

[Coreymacc]

Make sure your chimney is clear. I know some on here think I'm nuts but mine will burn back through the auger if my chimney is plugged with creosote. And that advice came from the manufacturer.

Corey

 

[SmokinEdge]

I agree you should cool down from high temps before shut down that will sure help.
As a side note, I have a GMG that started burn back. Would create burnt or black pellets in the hopper. With the GMG, they have a hopper fan that maintains positive air flow and pressure, if you will, to the fire pot. This stops burn back. In my case, the screen covering the fan had plugged with sawdust and lignin effectively cutting off air flow. I took it apart and replaced the screen and everything went back to normal.

 

[its a gas]

bumped for update

 

[Cody_Mack]

I have been having issues with my Camp Chef since not all that long after I bought it. I started having issues with burn back through the auger. The first time it happened I blamed it on Operator error for some reason; I think I used not cleaning out the ash tray as an excuse. Well I got more attentive to that and made sure I cleaned it out often. But I kept having issues and then I realized it happens only when I try to heat up the grill past smoking temps, which is not often.

Recently I was bringing it up for a long slow cook, and said what the hell, let’s see if it will go to 350. It did not, and by the time I got it completely under control, I had a whole hopper full of half-charred pellets!

Then I really got to researching the cause, and came across this post. I thought, how could that 2” stack possibly be stopped up, but what I didn’t realize is there is a grated opening from the pit to the stack, and the grate openings are not that far apart. The manufacturer calls it a screen, although it is actually an integral part of the grill body. Thank you its a gas and C Coreymacc for your comments that made me dig in more.

So I removed the stack and found what you see in the photos. Very interesting design, for sure, and it is mentioned in the manual to address the issue twice per year. I obviously overlooked this. Gonna give it a good brush-down and give it a go tomorrow to see if the grill will heat to 500 like is designed to do. Actually I would recommend not just brush from the inside per the manual, but go ahead and remove the stack on the outside for a thorough cleaning. What you see in the photos I just poked through the slots with a flat screwdriver.

Not sure if this applies to other pellet grill brands, but maybe it gets your attention enough to check it out.

From inside and then outside the grill with 2/3 of the screen cleared, then from outside with all cleared. Would like to hear comments on the design.

 

[tbern]

Thanks for sharing this reminder to do this cleaning!

 

[Coreymacc]

I called camp chef when i first had the issue of burnback through my auger and the stack screen was the first thing they mentioned. Mine was plugged 80% or more. Now i look at the screen weekly, i take my grill brush and clean the slots out. Cleaning the slots with my brush caused another issue however, when the soot falls off the screen, some goes out and some falls inside the stack. Its built with a 90 deg turn so it holds all that soot, eventually the soot piles up and covers the slots no matter how much you clean them. Removal of the stack and a good cleaning is the only way to ensure its clear. I do mine every spring for the grilling season. One other thing i found will cause auger burnback on my campchef is if you don't vacuum the ashes out periodically from around the burn pot. The ash covers the air vent holes and the burn pot will draw air from the auger instead causing burnback. Once a month i give that a good cleaning also.

Took a few scary moments to figure all this out but if i follow my cleaning program, i never have an issue and have confidence i wont find a fire in my pellet hopper.

My 2 cents
Corey

 

[DougE]

I don't know if it would have continued because I was there to stop it both times, but the two times when I have run my Camp Chef on high to sear something, a ton of smoke started billowing out of the hopper a few minutes into the shut down cycle. What I did when it happened was immediately empty the hopper, shut it off, then run the feed cycle to clear the tube out. With all that smoke coming out of the hopper, I suspect the pellets in the auger tube has started to burn. I have other means for searing and have never had an issue running it at 300° or less, so I just don't run it on high.

 

[Coreymacc]

The first time i noticed it happening I had zero experience with pellet grills so i wasn't really tending it too well, the smoke from the hopper was going for probably 10 or more minutes. By that time the hopper was hot to the touch and really smoking hard, no flames but I'm sure it was not far off. Lucky my control board didn't feel the heat. I shut everything down and dumped the hopper, the auger tube was fully burned and the pellets on the bottom of the hopper were starting, this was a lucky situation for sure. Im now very careful about my cleaning.

Corey

 

[DougE]

The first time i noticed it happening I had zero experience with pellet grills so i wasn't really tending it too well, the smoke from the hopper was going for probably 10 or more minutes. By that time the hopper was hot to the touch and really smoking hard, no flames but I'm sure it was not far off. Lucky my control board didn't feel the heat. I shut everything down and dumped the hopper, the auger tube was fully burned and the pellets on the bottom of the hopper were starting, this was a lucky situation for sure. Im now very careful about my cleaning.

Corey

I now always, without fail, keep an eye on mine during shutdown no matter what temp I had it running at. The two times I think I had a hopper fire starting was enough for me.

 

[tbern]

good discussion guys, since i have a camp chef pellet grill. thanks!!

 

[bill1]

I don't use my pellet machines much for final high-temp searing, but I can see where that would greatly increase the probability of auger burn-back.
More and more machines have a pellet quick-release door on the hopper so you can empty all but the pellets that are currently in the auger, and then just purge out those pellets into the crucible. Good thing to do if you're concerned about rain or humidity locking up your auger with swollen pellets during storage.
But that's also a good trick during final sear to ensure that although your crucible may be raging hot, there's at least no more pellets to burn back. If you time it perfect, you can turn off your grill just as you pull your meat and while the auger is starting to run non-stop trying to drive pellets that aren't there. Worse case, it runs out after you've walked away and starts alarming on under-temp

 

[DougE]

If you time it perfect, you can turn off your grill just as you pull your meat and while the auger is starting to run non-stop trying to drive pellets that aren't there. Worse case, it runs out after you've walked away and starts alarming on under-temp

That would probably work but would require a little testing to get an idea of how long it takes to empty the tube on high.

 

[bill1]

That would probably work but would require a little testing to get an idea of how long it takes to empty the tube on high.

A revolution on mine is 90 seconds. (I occasionally check that on startup to verify everything is working normally.) Based on my auger pitch and length, it's about 15 turns from hopper to crucible, or ~22 seconds at full speed, no stopping, which is what you get when you open the lid and set the temp setpoint to max. It's pretty straight-forward.
It a bigger job to empty the hopper, but that's not a bad practice if you're worried about auger jams.

 

[JWFokker]

Just open the the cook chamber door when you shut down. The draft will pull air through the augur and the pellets in the pot will burn out quick. They all keep the fan on for a minute after shutdown anyway. I can only see this being an issue when you're running 400F+ and shut it off with the cook chamber closed, trapping the heat and maybe a significant amount of unburnt pellets in the firepot.

 

[mike243]

Pitboss runs the fan till it hits a certain temp, that can take awhile if I don't leave the lid open. I believe dust plays a big part in auger fires also

 

[DougE]

Camp Chef does a 20 minute shutdown cycle with no mention of lid open or closed, but I'm pretty sure I've experienced burnback starting when shutting down from high temps. No issues letting it shut down from 300° or so, but when initiating the shutdown cycle from high, I get a lot of smoke coming out of the hopper, which leads me to believe a burnback issue has started since it does not do this when shutting down from lower temps. Anymore, I try to plan enough time to reduce the temp for awhile before initiating the shutdown cycle.

 

[Cody_Mack]

Keep the vent 'screen' clean. That's what I learned from this thread.

Rick