stack size?

[doop]

Is a 10" diameter stack big enough for a 3x8 drop flue evaporator?

[maple flats]

? Mine came with a 12". A 10 will likely be OK but you might need a taller stack to make up for a slight undersized diameter. Start with 2x the length of the arch (16' in this case). If it does not draw well enough, add more height. That being said, if you are at the design stage, go to 12" now. Some even use larger on a 3x8.

[wiam]

My 2x6 came with 12" and works well with it

[doop]

Thanks, guys, I'm making my stack out of 2' by 3' s.s. so the biggest I can go would be 11" . I'll try going taller.