1400 Degree stack temp!!!

[Rossell's Sugar Camp]

My stack temperature is 1400 degrees. Would air over fire help to bring this down? Is there anything else I can do to increase my efficiency without sacrificing boil rated. I already have auf. And boil 130-150 gph on a 3x10.

[doocat]

Do you have your blower on a rheostat (sp)? Maybe slow the bower done a little. Air over fire will if you put air blowing forward from the rear of the firebox.

[maple flats]

my stack temp dropped about 3-400 degrees when I added AOF. While I didn't have 1400 degrees, I did get up to 1200 sometimes before AOF. Now I am usually between 750-900 max and my boil is faster. I have both AUF and AOF, both on a single high pressure blower, and each is controlled by a valve. The AUF has it's valve at about 25-30% open and the AOF valve is open about 65-70%. THe HP blower pressurizes a 4" PVC pipe, outside, then under the arch it splits into 2 3" PVC pipes, each has a 3" ball valve (The HP blower & the valves were free to me, from an old factory being cleaned out). Then the AUF has a single 4" galv duct that enters from the back and lays on the floor. It has 3 rows of 1/4" or maybe they were 5/16 holes, spaced about every 3", 1 is top center and 2 are offset to blow at the outter sides of the grates. Then the AOF just pressurizes a 2x2 manifold the surrounds the firebox, set in the brick 6" below the pans. There are 1/4" black pipe nozzles spaced every 6" and each is angled down about 12-15 degrees. 2 of those nozzles are one each side of the door, aimed to the back, the sides just aim at the opposite side and 5 onlng the back point to the front. My nozzles are 1-2" longer than flush with the brick/refractory. I thought they would burn off with time, but must be the cold air blowing thru them protects them, they still look like new, after about 5 seasons use.

[WESTVIRGINIAMAPLER]

I have tried everything and I get the best boil rates when my evaporator runs 1200 to 1400 degrees. I have AOF on all 4 sides and have the opening to the stack closed down to about 3" and it doesn't matter. I can slow down AUF and it will go down drastically but so does boil rate. The wood usage is less but in the long run it doesn't save any wood as it takes longer to it is a wash. If you are getting that kind of boil rate, keep it cranking. I have played with mine for 10 years and now I want to see the temps stay between 1200 to 1400 degrees. We fire every 10 minutes. I have tried every other firing combination from 4 minutes to 15 and everything in between but this works best. My trusses are on 2' centers and have them covered with 1" ceramic blanket to be safe out 2' past the stack on each side. I have seen it over 1700 few times.

[maple marc]

In my experience on my 2x6, wood quality and size may be the most important factor in stack temp. With very dry hardwood, split into pieces the size of your forearm, the temperature can get too hot--up to 1600 without a blower, way too hot, of course! On the other hand, Less dry wood in bigger pieces yields temperatures in the 800 to 800 range, which seems more efficient. Every year our wood is a little different, and we try to adjust accordingly.

Marc

[maple flats]

I checked my stack temp yesterday when the pans were at a hard rolling boil , the AUF and AOF were on since lighting the fire and it was extremely hot in the firebox, my stack temp was at 575 F as determined by a thermometer probe IN the stack at 4' above the arch. Using AOF lets you use the heat under the pans rather than to sent more heat up the stack.