smoke stack not getting hot, making creosote, please help

[jakecode]

i am having trouble with creosote dripping back down pipe, you can put your hand on the stack after 4 hours of boiling, its not getting very hot at all, i have a homemade blower putting air under fire, is it to much air?
thanks guys
My wood is dry and it is split small, Just wondering how much air i should add under fire, and if it is causing my creosote problem

[nymapleguy607]

Creosote is from incomplete combustion, sounds like you fire isn't hot enough. How big is your wood, how often are you firing and how much air is going in under the fire. Wood needs to be dry and split fine (about wrist size) you want as much flame as possible.

[jakecode]

thank you Jeff, my wood was cut in july and piled under cover until now, it could probably be a little drier i guess, it is split wrist size though, i did have a leak in my preheater that sits just in front of the stack, do you think this leakage could of had a effect on stack temp? like carrying moisture thru

[Sugarmaker]

Jake,
need some more info on your set up.
Size of arch/pans?
length/ size of stack?
Blower type size/ position?
Grate size, firebox size?
Get a stack thermometer from a wood stove store to attach to the stack for monitoring.
In most rigs they burn hot enough that creasote should not be a issue.
Regards,
Chris

[jakecode]

Hi Chris,
i have a 2x8 rig, and a homemade blower under wood blowing straight up, my preheater pan is 2x2x1-9 high copper with flues, which was leaking, i wonder if the leak caused moisture to be carried up into stack and keeping it cool then dripping, i do have a stack thermometer which is reading Creosote, to cold, you can honestly keep your hand on stack after 4 hours

[jakecode]

the stack is 8" dia and pretty high, not sure exactely

[Sugarmaker]

Stack size and height sounds right.
Leaking sap may not be contributing to the creosote issue. But may need to be addressed depending on how bad it is leaking.
My guess might be wood that may not be as dry as you think? Can you get any dry stuff like pallets? More/ hotter fire is always better.
Should be like a inferno in the fire box??
Regards,
Chris

[Woodsrover]

Sounds like you need a bigger fire? That's a pretty long arch. I have a 2x4 arch and no AOF and I run a constant 600 stack temp. (I have a fan but mine seems to run better without it running.)

[bstewar]

This thread is very interesting to me. I have a drop flue 2x6 and have been thinking my 10" stainless stack isn't getting that hot. Problem is I don't have a temp gauge on it...yet. I'm comparing to my old 8" stack with galvanized base. That thing got really hot. My boil is good however I do need to make improvements under the flues as the gap from the bottom of flu to the blanket is a bit too much.

I noticed if I forget to shut my chimney cap and I get moisture/rain I get a soot running out of one stack seam.

[BAP]

How big is your blower? Sounds like you aren't getting enough air. I have a 2x8 and the first blower I used was an old oil burner and it did not put out enough air. I bought a blower off Amazon that is a Dayton 2 speed roughly 270/460 cfm's. My pans boil like crazy in fact I need to build a shield for the flue pan because the sap wants to jump out of the front 16".

[jakecode]

my blower is pretty big, i have to turn it down as my front is not airtight and i get to much flames out the front doors, i am going to check amazon thank you

[jakecode]

Hey guys, thanks for all the help, i had it roaring last night, it turns out there was to much vermiculite blocking the air flow under the flue pan not letting it breath, what a difference once i figured that out

[bstewar]

Hey guys, thanks for all the help, i had it roaring last night, it turns out there was to much vermiculite blocking the air flow under the flue pan not letting it breath, what a difference once i figured that out

What did you settle on for clearance from the flue's to the vermiculite?

[jakecode]

I did not measure it per say, looks to be a good inch gap on the back side of the pan facing stack, i think a squirrel over the summer may have bunched some up in places under the pan i could not see, i poked around with my long flue brush and its working well, stack got hot within a few minutes and boil was hopping best i have seen in awhile, made about 2-1/2 gallons last night for first draw this year, started with about 240 gallons of sap, pans are full and have about 30 in a preheater

[Sugarmaker]

Ok I am glad your getting better results.
Poking around with a flue brush worked. But I would at some point take the rear pan off and size the ramp to be correct for the size rig you have. I am not the expert on raised flue pans and or the dimensions of the openings for the heat to pass through. others can help when you get to that point.
Your doing good!
Regards,
Chris

[maple flats]

When you get a chance you should remove the pans (yea, not liquid in them) and smooth the vermiculite and either spread some powdered refractory cement of better a layer of half brick (if doing the refractory, just mist it with a very fine mist of water, and repeat about every 15-30 minutes if during a break in the season, if in the summer, dampen every day or 2 until it has been dampened about 10-15 times). The fire will harden it and keep the space proper. If a drop flue you only want 1/2-3/4" max, if a raised flue only 1/4-3/8" max. That will force the heat thru the flues.
Until you can do that, just enjoy making syrup.

[jakecode]

thanks Dave, cant wait to try your fixes, this evaporator came lined with the bricks and then they put this vermiculite on them, but they are loose and look almost like blown in insulation only smaller

[bstewar]

When you get a chance you should remove the pans (yea, not liquid in them) and smooth the vermiculite and either spread some powdered refractory cement of better a layer of half brick (if doing the refractory, just mist it with a very fine mist of water, and repeat about every 15-30 minutes if during a break in the season, if in the summer, dampen every day or 2 until it has been dampened about 10-15 times). The fire will harden it and keep the space proper. If a drop flue you only want 1/2-3/4" max, if a raised flue only 1/4-3/8" max. That will force the heat thru the flues.
Until you can do that, just enjoy making syrup.

That is my plan over the next couple days...remove the flue pan and reduce clearance to 1/2". Right now the fire blanket is within 3/4" but only for about 6". The rest is 1.5 - 2.5" and I can see the flame dip out of the flues in that section. Thanks for the info!

[chep]

I had an issue the other night boiling. Firebox was ripping hot and front pa was boiling great, but no boil in the back pan and my stack was cold. I'm on a 2x7. I messed with the arch preseason building up the sand closer to my flues. I took off a spacer in front of my stack and saw I had constricted my flow by having no space leading into the stack. I pulled out a bunch of sand and created a depression under the stack. So now heat is constricted into the flues then can expand into the stack at the end. It made all the difference rig is boiling great now.

Ben