I stuffed the stove full, all N/S. T-stat was wide open, visible flame in the box, stack probe @about 300F, CAT temp @ less than 400. Bypass open, so most of the heat should have been going straight up, correct? I kneeled down, and the CAT was bright orange-hot! Closed down what I needed to, and CAT probe went to 1000 in about 2 min. SO.... what is the lag time? I don't recall this scenario in "Pen"'s research.