I believe that's the first chimney fire I ever heard about on an evaporator. Creosote is generally built up when a fire is choked down and run too cool, not when it's fired hard. In 19 seasons I never cleaned my stack and it's single wall for 12 out of 17' total length. The 5' not counted is insulated from 1' below the bottom cord of the trusses up to the roof steel. My stack runs at 650F up to about 950F once it gets going.
In the off season did that pipe get used for another use? Maybe a smoker?
Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.