Hi, I am reposting this with a new title as another member thought my original title lacked the emphasis to get noticed. Hopefully this is better! I got a couple great responses, with the first post, but more input would be welcome! We purchased an Arrow 1800A woodstove a couple months ago to replace our old Earth Stove, which had developed cracks in the firebox. The stove has been great, and heats our house nicely, but every once in a while, maybe two or three times in a 24 hour period, it will emit a single, loud cracking noise (definitely from the stove, not the chimney or pipe) when it gets up around 450. We put it down to the expansion/contraction of the steel firebox, and didn't worry much about it. In the last week or so, though, it has started to emit smoke even when there is a brisk fire going (350-450). It seems to get worse when we damp the stove down. There are no visible cracks in the box, and the firebrick looks fine. We did notice a couple of vertical cracks in our cinder block chimney facing, but we're not sure these are new. The chimney is about 25 years old with a clay liner. We have never had any problems with it, and it was professionally cleaned about 2 months ago. We have stopped building fires until we figure out what is going on. Any suggestions or advice would be greatly appreciated!