SmokeFire, auger & hopper burn back.

[Bob Erdman]

I'm not sure what else could have caused the burn back. A Pellet void and excess Pellet dust being feed down the ramp from the auger into the burn pot seems like it could happen. The larger pellets in some brands do get chewed up in the SF.
I will be vacuuming the hopper more frequently now that's for sure.

 

[Bob Erdman]

Did the app show any significant change in temperature?

No, but I knew there was a problem when the temp dropped to about 220f. It was rock steady at 225f all night until then. Good thing I checked when I did because that's when I notice the smoke coming from the hopper, nothing from the vents.

 

[ChuckO]

That auger is pretty pitted, there was enough heat on it burn pellets in the chute. I’d go so far as to say that it was flaming and the flames backtracked to the hopper. Either that auger quit spinning with pellets in the chute or the motor somehow heated the auger. Do you have the latest in auger assemblies? You would know because it would have come with a bolt where the auger connects to the motor. I’m pretty sure Weber will replace it if it’s not the latest version

 

[Darian Hofer]

Bob, do you have any photos after your cleaned the auger and the shoot tube?
Mine looked similar after a burn back but cleaned up like new. Not that it helped it from happening again.
My Smokefire was the first pellet smoker I owned and took apart to see the build quality. It was not until I purchased my 2nd pellet smoker I realized how small the Smokefire auger and tube were in comparison.
I believe your above comment is very viable. Pellet dust build up caused from non standard size pellets in the mix and or weak pressed pellets being crushed in the auger. Very similar to the dust flashbacks that occur in a grain elevator conveyor system that can catch fire or blow out and explode like dynamite. I really believe many of the Smokefire issues are caused from Weber using a smaller tube and auger system compared to some of the other companies. I have no idea how the new Searwood compares with auger and tube size. Maybe someone who has owned both can chime in?

 

[Bob Erdman]

That auger is pretty pitted, there was enough heat on it burn pellets in the chute. I’d go so far as to say that it was flaming and the flames backtracked to the hopper. Either that auger quit spinning with pellets in the chute or the motor somehow heated the auger. Do you have the latest in auger assemblies? You would know because it would have come with a bolt where the auger connects to the motor. I’m pretty sure Weber will replace it if it’s not the latest version

I have the V2 SF. The auger has the nut and bolt. Six months ago, Weber sent me a replacement nut when I noticed during a cleaning that the nut was missing.

I can only guess If the motor/auger stopped running during the burn back. I think it was running, feeding pellet dust to the burn pot. I did a shut down immediately after seeing there was a problem and didn't notice if the motor was running.

To confuse things further, before the burn back there was a pellet void that I caught, or, maybe I didn't. There was 30 minutes between the pellet void and me noticing a temp drop and hopper fire. If I had a flame out from the pellet void I would have expected to see a bunch of unlit pellets in the burn pot. There were none in the burn pot. The one time I had a flame out there was a huge pile of pellets in the pot/grill.

 

[Bob Erdman]

Bob, do you have any photos after your cleaned the auger and the shoot tube?
Mine looked similar after a burn back but cleaned up like new. Not that it helped it from happening again.
My Smokefire was the first pellet smoker I owned and took apart to see the build quality. It was not until I purchased my 2nd pellet smoker I realized how small the Smokefire auger and tube were in comparison.
I believe your above comment is very viable. Pellet dust build up caused from non standard size pellets in the mix and or weak pressed pellets being crushed in the auger. Very similar to the dust flashbacks that occur in a grain elevator conveyor system that can catch fire or blow out and explode like dynamite. I really believe many of the Smokefire issues are caused from Weber using a smaller tube and auger system compared to some of the other companies. I have no idea how the new Searwood compares with auger and tube size. Maybe someone who has owned both can chime in?

I have not cleaned the auger or tube yet. I've used the grill without incident a few times since the fire. Nothing overnight though.

After reading some articles about burn back in pellet grills, it looks like it can happen to any pellet grill. That's a scary thought! My burn back definitely has me concerned, the wife more so. What's so frustrating is that there is nothing I can really do to prevent this from happening again other than doing frequent hopper vacuuming and hoping it doesn't happen again.

It's not a matter of if, but when will it happen again?

 

[LMichaels]

It was advised to me, the key to avoiding burn backs are to be on top of basic maint better (admittedly the one I had was likely my fault). I'd been lax about keeping the level of ash in the fire pot down. I am usually pretty good about getting my little shop vac in there at least every 2nd to 4th cook (depending on lengths of previous cooks). And when it happened I'd let a HUGE pile of ash build up. (had slipped my mind due to so many other things going on). I knew it was due but forgot how "due" it was
I also had just finished a high heat steak cook. At about 475 deg. And I put the grill directly into shutdown from high heat and went inside to finish prepping and then to have the meal.
Oddly the grill's (I guess most of them) shutdown mode is not by temp but by time. So, I put it in shutdown, the ash pile was up to the level of the auger, thanks to my 475 temp cook when the fan cut off there were plenty of very hot ashes that just could not wait to have a party in the auger. Was only when I went back outside to pull it into the garage I noted smell of smoke and almost ignored it. But, I opened the grill lid. Nothing, but opened the hopper and smoke coming from the hopper.
So, I drained the hopper (thankfully the fire had not reached the bottom of the pellet pile). Once drained I did a restart on the grill, and put it into prime mode, to force out as many as I could. Next AM I vacuumed out everything. Been fine since.
Since then I never do a shutdown directly from high heat on either grill. My thinking is on any given time IDK what had been happening in the pot. So, my shut down process is to step. Turn the grill down to a lower heat or "smoke" setting. Let it run that way, then once it's stabilized shut it down. I guess it wastes some pellets but rather that then a burn back