If I may, I'd like to pick the brains and mine the experience of the Elders who have weighed in on this topic. I am using an old Home Comfort cook stove, no cat, not air-tight, and no air tubes that would create a deliberate secondary burn. It is an old-school smoke dragon for sure. But every once in a while, I seem to get temps, as measured by my magnetic stack thermometer some twenty inches above the stove, that are way higher than what the stove usually produces given the same wood and same air. No roaring draft, just a lot more heat. I open the door and peer in, and the flames are not all that raging, either. I would surmise that, without setting out to do it, a secondary burn has been established. Which is Great, except that this takes the chimney temp straight to the top of the safe-zone (300 C) - and beyond. Luckily, I've been standing by every time this has happened, and I've been able to shut off air and close the damper and get things under control quickly. Anyone have an idea of what is going on here? Also, if I were to replace this old smoke dragon with a non-cat EPA secondary burn type stove, will the stack temps do the same thing? And would that be safe? Thanks for your thoughtful responses.