OK, in brief. Cleaned the stove. Two splits N/S, cedar shake in the middle. Lit it off, waited 1/2 hour, added 2 more E/W. All the temp. guages looked fine-(top, cat., and flue). Closed bypass, nothing out of the normal, T-stat @ 2.5 by this time. Wife say's"Let's trim the cat's claws!"- OK- 1/2 hour later, I smell something. Check stove, top barely 500, BUT- Cat is N of 2200 on the gauge, flue is 1100 and climbing. Smoke off of upper connectors( dbl. 45's), and the temp. is still going up. I closed the T-stat, opened the T-stat, opened the door , bypass open, bypass closed, door closed, almost any combo you could imagine. Cat. maxed @ about 2200, flue @ 1410. All good now, but that was strange- in a bad way. Now the kicker- in that time frame, outside temps. dropped almost 7 °F , and 1/2" of snow fell. Still snowing right now. Happened quick, so could that be a contributing factior? I need to blame this on something, 'cause I need to excuse the huge wad of Kleenex I have stuffed in my butt right now. (nevermind the totaled BVD's). :-S