Caution: Even w/manual fan switch on Pellet Smoker

[Smokin Don]

Over a year ago I installed a manual fan switch on my Traeger to take care of burn back in the auger tube after shutting down; I had several times. I have never had a problem, after smoking I turned the smoker off and the fan switch on and ran for at least 15 minutes to burn up the remaining pellets. Today I had just done a pork butt and had it in the oven resting.

I went out with a cold one and the fan had been running at least 20 minutes. I was about to turn it off when I noted some smoke coming from under the pellet hopper lid. It was only half full so I emptied it out down to the auger to run the pellets out.

I had some loud crunches coming from the auger then it cleared. Not sure what happened, think maybe I had a pellet jam and a void in the auger and that let it easily suck air from the pellet bin. Anyway even if you have a manual fan switch keep an eye on it when shutting down. You don't want the fire to get back to the pellet bin. Smokin Don

[teesquare]

Good post Ed! And - a good read for all pellet grill owners
T

[muebe]

What happens is the pellets at the very end of the auger tube get hot and ignite/ember. The fan is blowing air into the firepot and that air is feeding oxygen to the ignited pellets still at the end of the auger. Then the other pellets in the auger start to combust making it's way back into the pellet hopper.

Pellet grills with a hopper fan stop this from happening by for forcing air down the auger. That is why some pellet grills will not operate correctly with the hopper bin lid open. I believe GMG have this feature.

Pellets grills with a cool down mode will run the fan and activate the auger motor every couple minutes dropping a few pellets as it cools down. By doing this it allows any pellets at that end of the auger that are ignited to drop into the firepot. This is why even after my Memphis is off I can still hear some pellets drop from time to time while in cool down mode.

[smokeasaurus]

That would be real scary if that fire got all the way to the hopper.

[GrillGeek]

It's a good idea to set the grill to it's lowest temp and let it come down, and then put it into fan only mode...

I've had hopper fires in the past by shutting the grill off when it was too hot.

[Smokin Don]

It's a good idea to set the grill to it's lowest temp and let it come down, and then put it into fan only mode...

I've had hopper fires in the past by shutting the grill off when it was too hot.

Thanks GG that's what I didn't do and good point to remember! Don

[hikerman]

My GMG does have the fan blowing down the auger to prevent burnback , and the manual states that it should be turned off by turning temp. down to 150 and clicking down button once more. This starts fan mode for 15 min. Both hopper  and combustion fans run at this time. A nice safety feature, and whether your grill has that or not, like GG said, it's a wise thing to do before shutting down.  Thanks for bringing this up Don!

[smokeasaurus]

Luckily my Yoder has the auger opening about 3 inches above the fire-pot and the pellets drop off into it...so I think I am safe on burn backs 

[muebe]

Luckily my Yoder has the auger opening about 3 inches above the fire-pot and the pellets drop off into it...so I think I am safe on burn backs 

You are not 100% safe smoke. My Memphis has the same design but if the firepot is a raging inferno you can have a burn back. That is why Memphis and MAK continue to drop pellets during the cool down mode. I assume the Yoder does the same. They put this feature in for a reason

[smokeasaurus]

That is good to know and kinda scary    I know when I shut the Yoder off, the fan stays on until the internal temp of the pit reaches 150 degrees.

[muebe]

And if you listen close you may hear a few pellets drop during that cool down period. That is normal and is for safety.

[smokeasaurus]

Yeah, they do.