I had a few times when the pellets would not slide down the chute after igniting, but kept feeding. This caused them to burn their way up the ramp to the auger. I always caught this before they reached the hopper. I had to slide them down and clear the chute, then everything worked OK. This was on my 500. I had to make sure it was level, or this would happen more if the trailer was too high on the slide side.