Stack pipe question on block evaporator

[valleyman]

I re worked my sugar shack roof so the center panel is now hinged so I can lift to allow steam to escape. The stack went through the roof before the modification. Now that it lifts I had to move the stack back. So I now have a 2 foot horizontal length coming out of the arch before going 90º up 9 feet. How will the horizontal length effect the draft?

The block arch is about 2'x4' (4 steam pans)
Thanks

Greg

[Ecnerwal]

More or less makes your effective length 2 feet longer - but that's only 6 feet, so you still have 3 feet more up than you have horizontal. I think that puts you theoretically good, but if it seems to have issues, slap another section of stack on it. If you set another steam pan over the horizontal section of pipe to preheat, you can even get some good out of it...

[valleyman]

Ecnewal,
Didn't even think about utilizing the extra pipe for a preheat. Thanks.