Send them a link to this thread, so they can see how their response sits with people that likely have many more years standing over a cooker than they will likely ever have.
Emphasis mine.
They didn't blow me off by simply saying, "It's the wind." We went back and forth through several emails with them asking me to check to ensure a couple of things were working. We ultimately couldn't determine the issue. During the troubleshooting process, I recorded several videos. Here are two of them:
After 240 views of this thread, no one has pointed out anything totally obvious to this being caused by me. So, the MFR is GMG. During my troubleshooting process with them, I took some videos (linked above). A week or so after taking those videos, I checked the weather for that day. Wind was gusting up to 20 MPH. The smoke wasn't always blowing back through the hopper, just sometimes. I thought that maybe it was the wind, offered that as a solution to them. They didn't tell me I was wrong.
Here's something they told me in an email:
Chimney Cap: If I see any air flow troubles, I always raise the chimney cap all the way up.
Hopper Lid: If your hopper lid doesn't sit totally flush on top of the hopper box, the pressure from the hopper fan can be lost. An easy test for this is running two sheets of tin foil over your hopper to make a temporary air tight seal, closing your lid over that, and running the grill to see if you have smoke that comes out of your hopper.
Combustion Fan: If pellets or debris fall through the burn pot and damage your combustion fan, or if your combustion fan just doesn't spin freely inside of the housing, the lack of oxygen will let the fire travel into your auger.
Hopper Fan: While the fans are running, you can open your hopper lid and put your hands over the vents that the hopper fan blows through. You should feel air flow into the hopper from those vents.
Burn Pot: Must be clear
Pellet Dump Door: (if you have one) must be securely closed down. Often it doesn't get pushed all the way down and leaves a gap which lets out pressure from the hopper fan. if not slid down all the way it can have the same effect as an open hopper lid not being shut.
My chimney cap is all the way up. Honestly, I'd figure that you'd want it down to keep wind out. Better yet, I'm thinking an angled piece of metal would be better. Something you can rotate so that wind can't blow into it. Better than that would be a cap on a bearing that rotates with the wind automatically. These auto-rotating caps are available for vent tubes from house attics, wish we had one for smokers.
Hopper lid is closed.
Hopper fan is working. I watched it from under the hopper.
Combustion fan runs.
Burn pot was vacuumed out before taking those videos above. I vacuum it typically every other time I use the smoker for short cooks, like ribs. For butts and briskets, I'll vacuum it every time I use it.
Maybe there's a partial blockage in the auger tube? Like some wood dust stuck to the auger? Maybe some pellet dust was in the tube and acted like a fuse and burned back up to the hopper? From the videos, it seems like the combustion fan blows far more strongly than the hopper fan, like it is forcing backflow. I do have a crappy homemade downdraft in the smoker. It's just a 3" pipe with a 90 degree bend that goes down to the grill grate. I've been considering removing it. I'll toss it now.
