I think down to 300 but I put wood in and climbed to 600 in minutes and from there steadily climbed, I was pretty happy with how cat operated. Climbed to 1500 briefly at peaked then settled btwn 11-12 for while then settled again at 900 for long time then slowly dropped. Stove top took bout an hr to get to 400 then slowly climbed to 750, stayed for good half hour then settled round 600. This is with air and damper closed entire time. That’s what bothers me if it would have kept climbing which I think it would of with more wood I had no way to slow it.Do you know what the cat was at before you loaded it up?