I've said this before, but this morning I got a classic case where watching just the stove top temp is not a good guide for when to start shutting down the air. We had a mild evening yesterday and I was busy. We let the stove die out overnight. This morning was a cold start. I loaded the stove with a couple decent sized fir splits with kindling in between ala tunnel of love style. The fire slowly built up enough so that I could place another big split in the center over the tol and two splits on either side of it. Went in to answer my email. Came back to a serious blaze; the flue was past 1000F and climbing (probe). I shut it down quickly to 1/8 air and that tamed the fire. Stove top was only 275. Lord knows what temp the flue would have been had I waited to 400F as many like to do. Moral of the story: There are times when you need to trust your eyes more than instruments. epilog: 7 minutes later and the flue is down to 500F with a 475F stove top. I expect when I head out the door that the stove top will be hitting 650F and the flue around 450F.