I've been burning the American harvest 6100 (bought used) for 4 years or so, mostly with corn, but now with pellets only, considering the cost. It's run pretty well, and I'm familiar with many of the troubles like broken auger pins and clogged airways. Recently it's given me a lot of ERR-3 faults, even though there's a good fire in the pot, from HR 1 to HR3. I hesitate to just start replacing parts - I didn't get the thing so I could empty my checkbook. Diagnostically, I wonder if I'm losing the temp sensor at the output, but can't tell what it is, so I wonder how to test it. Cleaned the whole unit and it ran a few days. Smokeways and room airways are a lot cleaner than last year at this time. Cleaned everything again, but can't keep it running. Room fan starts and it puts out plenty of heat, but within 30 minutes it decides it is not sufficiently hot and shuts down, filling the place with smoke. Granted it's in a cool basement, but that's where it's been for 4 years. Made no changes to anything. But can't keep it running for the first extended time ever. I'll still clean the whole thing one more time from the hopper to the vent pipe, but I just did that 2 weeks ago, and have never had to do that more than spring and January for previous 3 years. Anyone had experience with such a challenge? Would appreciate ideas of where to look for trouble. Thanks for any help.