10 in. chimney too big?

[beehappy1950]

Hey, I might have a deal. I need to know if a 10 in. chimney is too big for an evaporator. My pans are to be 27 by app 90 in next year. Got a chance at a stainless auger tube 20 foot long. It is 10 in tho and I had a 6 in. this year. I was planning to move up to an 8 in. but if 10 will work then stainless we will be.Harold

[Bucket Head]

It should work fine. My homemade 30"x 72" has a 12" stack. Its better to have a stack a little too big than too small. You don't want to hinder the draft. You can always install a damper if you think too much heat is escaping too quickly. I have a damper but I have played with the firebricks too at the rear of the rig where the flues end and have adjusted for draft and heat loss there. I don't use the damper now and it boils fine.

Steve

[maple flats]

my 3x8 has a 12" and works good. Give it as much air as you can for a HOT burn.
I used to get stack temps of 850-1000 when naturally asperated, this year I added high pressure air, under and over the fire. I now get a faster boil and after learning where to set the flow control valves I get stack temps of 650-800 but mostly 700-750. This shows I get better efficiency (less heat up the stack) The 10" should be perfect for your size arch, but tru to get some over fire air if possible. It creats turbulance and burns more gasses before they go up the stack. The way to know if you have much unburnt gasses is to look t the top of the stack in operation in the dark. If you have fire out the top it is gasses igniting as they get some air, they are not a flame from the firebox.

[beehappy1950]

Thanks for the help on the circumference, now how tall should it be? Harold

[Thompson's Tree Farm]

Rule of thumb is stack should be a minimum of 2x the length of the evaporator.

[ringer]

where is that measurement taken from

[Thompson's Tree Farm]

From the evaporator. Include the base stack in your height measurement.