Flue temp (digital probe in Selkirk DSP) went from 760 to 1040 in about 2minutes. I was in the kitchen and didn't know it was happening until the alarm went off at 850. I had been cruising on secondaries at 760. Burning only kiln dried (mostly ash) and 3.5 yr hickory and locust. I clean the flue with a Sooteater twice during the season, and once after. I have only ever gotten 1-2 cups of very fine black powder out of my 30' stack. With the 30' stack, my draft is very strong, and even with the flue damper closed all the way I normally have flue temps of 800-830 for a good part of the burn. I don't burn overnight, so no smoldering fires. This load had a couple of pieces of the kiln dried ash up near the top. When the temp shot up, the fire was about the same, very strong secondaries, some blue in there, all front holes on the baffle firing away. Is it possible that the ash shifted and outgassed suddenly, really quickly? The event only lasted about a minute (a very long minute, but no change of pants necessary), then the fire continued as before. No other signs of a possible chimney fire--rumbling, shaking, loud noise. Any one seen similar or have thoughts? Thanks.
