# Exploding Grill?



## Javaaman (Jun 19, 2018)

Just read a report about a pellet grill (not sure if I should mention the brand here) exploding and bursting into to flames. Seems the problem was started when the owner noticed the grill had gone out. He said he opened he hopper and noticed "....it had burrowed a hole down through the center, so it starved it of fuel". He said "he pushed the pellets back into the hole and turned the grill to smoke mode". This is when he said the grill started to smoke excessively and then "exploded". 
He said the manufacturer said this has happened before but offered no explanation why.
The report was courtesy of KEPRtv.com


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## SmokinAl (Jun 19, 2018)

Wow, that is scary!
I've had my gas smoker, kind of flare up when trying to light it.
If it doesn't light on the first couple of tries, then the gas fills up the chamber & when it does ignite it really flames up.
So now if it doesn't light on the first couple of tries, I just wait a minute, before trying again.
Al


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## gmc2003 (Jun 19, 2018)

Our pellet heating stove used to funnel out every once in a while. When it did we would shut it down clean out the burn pot and restart. I'm kinda puzzled as how it could explode though. Any more details.

Chris


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## Javaaman (Jun 19, 2018)

Gas I could understand. This, with pellets, I agree is scary! I suppose it's tied into "spontaneous combustion".


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## Javaaman (Jun 19, 2018)

gmc2003 said:


> Our pellet heating stove used to funnel out every once in a while. When it did we would shut it down clean out the burn pot and restart. I'm kinda puzzled as how it could explode though. Any more details.
> 
> Chris


Just what I provided Chris. I'm puzzled by the manufacturer's lack of response.


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## gmc2003 (Jun 19, 2018)

Agree, I would be worried about the manufacturers casual attitude towards this also.


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## SmokinAl (Jun 19, 2018)

I think it would be a good idea to post the brand name, so the guys with those units can be fore warned.
All your doing is repeating what you read. I don't see anything wrong with that. You could also put a link in here to the original article.
Al


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## Javaaman (Jun 19, 2018)

According to the article, Traeger is the manufacturer.
The article can be found at:
KEPRtv.com


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## Javaaman (Jun 19, 2018)

KEPR is a CBS affiliate in Pasco, WA.


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## SmokinAl (Jun 19, 2018)

Thanks, I had a feeling you were going to say Traeger.
Here is the link.
http://keprtv.com/news/local/west-richland-man-warns-others-after-pellet-grill-explodes
Al


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## gmc2003 (Jun 19, 2018)

I did a quick Google search and apparently this happens more frequently then expected. Most of the pellet heads think it's caused by a build up of pellets being reignited before the burn pot is cleaned out. Possible I guess. Here's a link to the original article. There's actual film footage.

http://keprtv.com/news/local/west-richland-man-warns-others-after-pellet-grill-explodes

Chris


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## Javaaman (Jun 19, 2018)

Thanks for posting the actual link guys. A "dinosaur" when it comes to "technology" LOL!


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## SmokinAl (Jun 19, 2018)

gmc2003 said:


> I did a quick Google search and apparently this happens more frequently then expected. Most of the pellet heads think it's caused by a build up of pellets being reignited before the burn pot is cleaned out. Possible I guess. Here's a link to the original article. There's actual film footage.
> 
> http://keprtv.com/news/local/west-richland-man-warns-others-after-pellet-grill-explodes
> 
> Chris



Hey Chris,
When you googled it, were all the pellet smokers Traeger, or were other models involved?
Al


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## gmc2003 (Jun 19, 2018)

Mostly Traeger's, but not all. I read about a MAK also. They all seem to follow the same pattern - flame goes out for some reason, and the owners trying to restart the smoker without cleaning the pot. Taking shortcuts is going to get someone hurt real bad.

Chris


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## radio (Jun 19, 2018)

Not sure about others, but the Green Mountain Grills have a "Hot start" sequence that should be followed.  Makes sense they all operate in a similar manner though.  Sounds like he did a normal start while there was still some burning pellets in the burn pot and it fed a bunch of fresh ones on top of those.  My GMG has a low pellet alarm which sounds if the auger is running out of pellets as I am sure others do also. 
Almost guarantee that Traeger will say it was operator error and do nothing.  One should always read the manual and follow the instructions


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## gmc2003 (Jun 19, 2018)

Here's a post from 2010 on SMF, very similar.

https://www.smokingmeatforums.com/threads/too-much-fire-traeger-help-sought.98605/

Chris


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## chopsaw (Jun 19, 2018)

Javaaman said:


> Gas I could understand. This, with pellets, I agree is scary! I suppose it's tied into "spontaneous combustion".



Semi burned pellets create a " rich " environment . When it leans out enough , like you said ,, it all goes at once . 
The very reason Masterbuilt says NOT to use pellets in a MES .


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## daveomak (Jun 19, 2018)

What was experienced is called a "flash over"....
A *flashover* is the near-simultaneous ignition of most of the directly exposed combustible material in an enclosed area. When certain organic materials are heated, they undergo thermal decomposition and release flammable gases. Flashover occurs when the majority of the exposed surfaces in a space are heated to their autoignition temperature and emit flammable gases (see also flash point). Flashover normally occurs at 500 °C (932 °F) or 590 °C (1,100 °F) for ordinary combustibles..

The hot pellets were emitting combustible solvents...   When the right conditions were met, those combustibles lit off...


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## Javaaman (Jun 19, 2018)

Am I oversimplifying it or is the solution to always keep the hopper full.


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## Geebs (Jun 19, 2018)

Chris beat me to the research. I was looking this up as well and saw its mostly Treager with a few MAKs in there. Very interesting and certainly would be scary. One guy said his brisket got thrown out onto the deck. I would not be very happy with this.


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## johnmeyer (Jun 19, 2018)

I "fixed" a friend's Traeger when it exhibited everything just described except, thankfully, the explosion at the end. The problem is that there is a design flaw. Because of this flaw, sometimes during operation, but mostly at shutdown, the pot fills to the top with pellets before the igniter is turned on.

When the igniter next cycles on when the pot is in this over-full condition, it can heat the chips to where they smoulder, but without enough air being blown through pot to actually ignite the chips into flame. More chips keep coming in from the loader, which continues to smother the ignition. The result? You get fantastic amounts of smoke; unburned chips get pushed up and over the pot edge onto the floor of the smoker, and the darned thing never actually ignites.

The solution is to turn the controller to the full off position, scoop all the semi-burned pellets into a fire-safe container, and then start it up again. It should work fine after that.

I expect the explosion was caused by the dust that gets created as the pellets get partially puverlized in the hopper and loader. If you have too many pellets in the pot, and lots of this dust is mixed in with the pellets, when the blower fan starts up, the dust hits all these glowing pellets and you could easily get the equivalent of the well-known grade school experiment where you create a small explosion using atomized flour.

Check out the following video that shows the power from even a really small amount of dust. All the guy did was load a little bit of flour into a funnel, and put a rubber hose at the end of the funnel so he could blow the flour into tiny little particles. The candle burning in the can provided the ignition.

Spectacular, eh?


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## RiversideSm0ker (Jun 19, 2018)

Offsets don't explode. That's a point in my favor woohoo. I work in IT but sometimes technology scares the crap out of me. Cars that drive themselves into a ditch are another poor example of trying to leap forward a bit too quickly. I like the idea of a pellet grill but if I were to go for a set it and forget it I probably would go with electric. Not that they don't have their own risks but that is just where I imagine I would go. 

George


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## gmc2003 (Jun 19, 2018)

Javaaman said:


> Am I oversimplifying it or is the solution to always keep the hopper full.



The hopper doesn't have to be full, just keep an eye out for the funnelling of pellets in your hopper, and if the flame goes out then don't try to restart it without cleaning the burnpit out. Restart it like you would do on your initial ignition. 

Chris


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## Javaaman (Jun 20, 2018)

gmc2003 said:


> The hopper doesn't have to be full, just keep an eye out for the funnelling of pellets in your hopper, and if the flame goes out then don't try to restart it without cleaning the burnpit out. Restart it like you would do on your initial ignition.
> 
> Chris


Good advice. Thanks!


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## hinds90 (Jun 20, 2018)

Saw this earlier doing some research because I was interested in a pit boss.


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## johnmeyer (Jun 20, 2018)

hinds90 said:


> Saw this earlier doing some research because I was interested in a pit boss.


Yup, that's exactly what I described in my post above, and the explosion looks very much like the flour explosion. Given all the air being pumped into a pellet grill pot, it only takes a very, very small amount of powder to create an explosion like this, if the pellets have pulverized. 

Actually, the more I think of it, I don't know why this doesn't happen more often because all the dust from the pellets will tend to go to the bottom of the hopper and therefore when the grill gets into this "flooded" mode, usually at startup, the first thing that will be pumped into the pot will be dust-rich pellets. The smoke, prior to the explosion, is precisely what I saw in my friend's grill while I was troubleshooting it. I now feel very, very lucky to have not been hurt. 

To me, this is a fatal flaw (grisly pun intended).


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## mike243 (Jun 21, 2018)

I changed pellet flavors fathers day and ran all of the hickory out of the auger tube and when the fire had died out took my air nozzle and blew the dust out of it.Not sure if it will help prevent this or not but easy to do,also the Manuel sez to not shut the lid til a fire is established,I wonder if all of them would do this while starting with the lid closed?


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## Blue Kettle (Jun 24, 2018)

Freaky situation for sure. What's concerning is my Camp Chef is almost continually doing the thing where it funnels out and I'm having to restart the fire on longer Cooks (you can say Keep It full but once you've done to bed...). Guess I I just need to be careful. Definitely makes me wish I'd just bought a 22 inch Smokey mountain and BBQ guru instead.


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## dward51 (Jun 24, 2018)

Is it possible that an environment favorable for the "gassification of the wood pellets" occurred?  There is a way to extract a burnable gas from wood and bio mass in a low oxygen environment.  Wood gas, also called “holzgas”, air gas or blue gas, is the product of thermally gasifying a biomass material. Wood gas is generated in a high temperature chemical reaction (>700°) between the wood and a limited amount of steam or oxygen. The heat and lack of oxygen causes the gases in the wood to release in the form of carbon monoxide, hydrogen and carbon dioxide. The hydrogen will burn (and could also contribute to an explosion in the right conditions).  It think this may be the same as the flash over DaveO was referring to.


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## hinds90 (Jun 25, 2018)

Yeah after finding these issues over the weekend I'm sticking with my 26 Weber kettle and IQ110. 



Blue Kettle said:


> Freaky situation for sure. What's concerning is my Camp Chef is almost continually doing the thing where it funnels out and I'm having to restart the fire on longer Cooks (you can say Keep It full but once you've done to bed...). Guess I I just need to be careful. Definitely makes me wish I'd just bought a 22 inch Smokey mountain and BBQ guru instead.


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## bluewhisper (Jun 25, 2018)

In structural fires, there is the phenomenon called a "backdraft" where a space like a room is hot enough to burn but it lacks oxygen. Open a door and let air in, and BOOM.


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