My most recent evaporator was a 3x8 raised flue. It had a hood over all, flue pan and syrup pan. Each had a 15" stack. I had a Y made to bring the syrup pan stack into the flue pan stack, it worked very well. The flue pan hood was 1 piece and the syrup pan hood another piece, but they were joined together straight across the top. On those pans I designed both, especially as to the height of each. The flue pan was 20" tall and the syrup pan was 14" tall. The hood over the flue pan was another 18" tall, while the syrup pan hood was only 10" tall, thus when they were connected across the top, and sat down on the flue pan I had about 14" open above the syrup pan, it worked very well. All of the steam from the flue pan and about 95% from the syrup pan went up the stack. I did have a slight bit of steam from the syrup pan that went up in front of the syrup pan portion of the hood. It was never a problem, it went up and out the cupola.
Dave Klish, I recently bought 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.