Where Did I Go Wrong?

[jesseeg]

Hey Guys, I need help. I did a test boil with my setup today. I was getting a hard boil over the firebox but no boil at all back toward the stack. I'll describe what we've built and I'm sure that y'all (I guess that gives a clue that I'm a Southern addict) will be able to tell me what I did wrong. My arch is a diesel tank 6 feet long and 3 feet in diameter. We cut a slice off the top to set a 2 X 5 flat bottom stainless pan that I bought from Bascom's. We welded a firebox 24" across and about 20" deep. From there, we ramped the firebox up to within 5" of the bottom of the pan and held that dimension all the way to the stack. The firebox is lined with firebrick and the passage is lined with an insulation blanket. The 6" stack and the door are from a Vogelzang barrel stove kit. I use a cast iron fireplace grate and inject air with a squirrelcage blower and a 4" duct below the grate. I am using dry pallet wood and slabs to heat with. 3/8" copper tubing runs from the outside storage tank to the pan. Along the way it takes 12 wraps around the stack to (hopefully) preheat the sap. As I said earlier, I'm getting a hard boil over the firebox but nothing in the back part of the pan. What am I doing wrong?

[RileySugarbush]

How long did you let it go? With a flat pan it may take a while for the back of the pan to get going.

You might want to minimize the depth of the flue under the pan. It doesn't need to be much if any bigger in area than the stack. The 6 inch stack has an area of 28 square inches, so a 1" gap would be plenty and it will keep the hot gases up against the pan. If the 6" stack starts right at the top of the stove, you will need to make sure there isn't a restriction at the bottom of the stack. Maybe drop the bottom of the flue area right at the end of the pan to open up that area.

[chainsaw]

I think your chimney pipe needs to be bigger in diameter. Sounds like the lack of draft. Pipes to small.

[RileySugarbush]

That's a good point, Chainsaw.
Did the stack get really hot? Get a stack thermometer to check.
If it did, then you have hot gasses going under the pan and reducing the area should help. If it didn't then you may have too small a stack, certainly too small w/o the draft fan.

[jesseeg]

I boiled about 10 gallons of water and I didn't time it but I think it took about an hour. The last 12" of the tank is still fullsize and the Vogelzang collar is attached there. I'm sure that an 8" stack would help tremendously, but it's not in the budget for this year. I will use a layer of sand or vermiculite under the insulation tomorrow to get the heat closer to the bottom of the pan. Since my whole range of knowledge on evaporator construction is based on what I have read here and seen in catalogs, I should have asked for advice before I started cutting and welding. I am hoping to get to look at Andrew Martin's setup this weekend if I am not too far behind on collecting and boiling. As far as I know, he is the only producer within a hundred miles of me.

[peacemaker]

well i also have made somewhat the same as u which i ran up to this year a 2x4 flat pan in the back and a 3 section front .. i use to have the same problem nice roll 1/3 way back of the back pan 3 mistakes i fixed one i had a piece of angel iron acrossed at u guessed it 1/3 back took it out but still didnt get the boil i wanted was boiling almost back .. went from 6 inch stack to 8 and better yet but still not nice all the way .. so how i had the cold sap coming in was from bulk tank into a 11/2 pipe reduced to 3/8 dumping in the back corner .. took that out ran flex copper all the way around the pan back to same corner sweeted it into a coffe can at the bottom and then let it fill and run over slowly now boil all the way back to the point it shakes the can all over i use to not be able to cut my draft back on the stack at all now i can ... which will move the heat up under the front pan for u also...

[Maplewalnut]

Try putting a firebrick in your arch just before your stove pipe. It will act as a baffle of sorts and redirect the flame and heat up before it escapes up the pipe.

[H. Walker]

How deep was the water? If it is any more than 1 1/2" it will be hard to get a good boil.

[WESTVIRGINIAMAPLER]

With a blower you should be fine and 6" is plenty of stack in my opinion as the blower is directing heat. I used to run a 5x7 stainless 4 section King Syrup pan with two 6" stacks on the entire pan and I could get around 50 gph and it pulled plenty of draft and I had the two stacks side by side in the center of the pan and the whole pan boiled good. Just give it some time and play with it, you will get it worked out.

[tapper]

Like Brandon said 6" stack should be plenty but with a single 6" outlet all the flame and heat is beig pulled toward that 1 opening. You either need an oval shaped base stack or at least 1 more 6" outlet like he ran. I bet you will see a huge improvement with 1 more outlet. But maybe y the 2 outlets together into 1 stack becauce I dont think you need the added draft of 2 complete stacks.

[Valley View Sugarhouse]

did you try with the blower off?? I have seen when ther is too much blower used and you are blowing the heat out faster then the pan can transfer..

[Fred Henderson]

A dam made from bricks right at the back of the pan so you only have a 1" space between the pan and the bricks will help to keep a lot more heat where it is really needed. That was the secert design that I had on my 2x6'6" flat pan. Except mine was a 1/2" steel damper that I could adjust. That rig would boil better and more than a 2x6 drop flue. Hind sight is the greatest thing in the world, I should have kept it.

[WESTVIRGINIAMAPLER]

Fred you will have the 3x8 cranking out gph you never thought possible this season!

[Fred Henderson]

Brandon,

Would you beleive that I had it doing about 90GPH last year. I have to keep the stack temp at 500 drg. I also picked up another 100 taps in the same grove that I was in last year. Going up there in a few days and run some tubing in on a gravity line. My bush is on the noth side of a hill but the new taps will be right up on top.

[WESTVIRGINIAMAPLER]

Fred,

Sounds good and will make for much shorter days and more syrup than you could have done on your other rig.

Have you got a blower on it??

[Fred Henderson]

Brandon,

No blower, but I do have 18 feet of stack instead of the 16 ft. I don't want to get done too quick. I like doing this and its just a hobbie.

[jesseeg]

A big "Thank You" for everyone's suggestions. I took John Bushey's advice and used some sand under the insulation blanket to bring the heat closer to the bottom of the pan and Fred Henderson's suggestion about using firebricks in front of the stack to direct the heat where I wanted it. With the blower going, I got a hard boil the full length of the pan. I'm sure everyone's advice would have worked, but those 2 were the quickest and cheapest. Now if someone just tell me an easy way to dig out a tractor buried in mud up to the belly. The worst part is it has my collecting tank and about 150 gallons of sap on it. Thanks again to the group.

[Ahnohta]

How about evaporating the mud.

[maple flats]

I have gotten tractors stuck as you describe. What I did was take some chain and run it under one axle and hook it to a slot in the wheel, the other end i hooked to a good size tree. As I let out the clutch the chain wraped around the axle and when tight it pulled the tractor out with very little effort. Do not try this if the wagon is frozen into the mud, you will have so much pull that it will break the trailer or wagon. While pulling it is best to have a watcher make sure nothing is getting caught such as chain on wiring under the fender etc.
Maple Flats

[jemsklein]

and i could tell you he have had are tractor stuck so many times and each time we use a diffrent way