We have just replaced our bottom auger and both motors. We keep receiving an E2 error. I have pulled both auger and cleaned them, had also used sandpaper to get build up off top auger. Turn stove on and it will run fine for 10 minutes or so. Once I add pellets to the hopper, the top auger only turns correctly for a couple of minutes, then jams. What else can I try to fix it? We are using the same brand pellets that we did last year.