Our Drolet ECO 45 pellet stove is still acting up. Anyways, it runs perfectly fine on heat setting #2, but as soon as we boost it up to #3, we get the H1 error code showing up after running for a few hours. We first installed our stove in Nov. '07 and had very few problems with it until H1 started appearing in early January. Now it seem to be a semi-permanent fixture, at least on 3. I know how to get rid of the code, but why is it doing it?? Does anyone have any ideas? We have also tried adjusting the damper settings, but it doesn't seem to be making any difference. The code keeps appearing. The heat exchangers were thoroughly cleaned, by hand, not just using the rod, the chimney and all exhaust parts were cleaned of ash, including the chimney.