On my 3x8 evaporator the firebox was 32" front to back and 25" wide inside the bricks at the grates. I cut my wood at 21" long, piled it in one criss crossed stack starting at about 6" in from the door. It boiled very well. After adding AOF/AUF I fueled it every 9 minutes, before the AOF/AUF I fueled every 7 minutes.
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.