stack fires !

[Three Saps Sugar Shack]

got a 2.5x8 grimm lightning... very dry pine for wood, raised flue , 12" stack approx 14.5' tall, and about every eighth hour of boiling i get a three foot tall torch type flame ,lasting approx2 min's. from the top of the smokestack , now we run an intense fire, and fill the firebox approx every 7 mins. nothing really has a chance to get creasote on it and with extremely dry wood...????? i just dont undestand it... anyone have an explanation?

[802maple]

If you are filling the firebox complete you are starving the fire for oxygen and when it hits the outside air it reignites, Try firing alittle more often with a smaller amount of wood and not so full of wood . I try to not fill the arch more than 2/3rds full in a standard arch and with a forced air arch no more than 1/2 full but I am putting wood in every 3 to 4 minutes very quickly

[MaplePancakeMan]

so thats how you guys load your evaporators? I fire every 15 min, if i do it any more often i have to shut the damper and open the door to get the boil down, and i only run about .75" over the flues. And i fill the box til its about 5 " from the pans

[WESTVIRGINIAMAPLER]

Three saps,

What kind of gph rate are you getting out of it burning all pine?? I would guess that the creasote is building up inside the stack because I don't think you can ever get all the resin out of pine.

[hard maple]

pancake man
Why would you want decrease your boil by munipulating the doors on your arch? just curiuos?!

[MaplePancakeMan]

because it either hops out of the pan or sometimes since i don't use defoamer, it foams up all the way to the top and with a layer of foam, it doesn't evaporate as much steam, it acts as a blanket and keeps it in. I've had the pan boiling up to the top of the pan and over from front to back. i dont get a good consistent boil in the front pan, the back two dividers boil much better than the front even if i build the fire just to the front. So anyway when i have that problem, to avoid a mess, i open the door and close the damper then as it goes down i close the doors but not 100% of the way, then i open the damper and close the doors and it ends up being ok, even when i fire it never really dies down, i'd love to be able to stop this but keep the boil really high. just not over.

[HanginAround]

Three Saps, I'm going with 802... I don't think it can be creasote at temps that high, I would say you have a very hot fire, high stack temps, and a lot of wood gases and resin gases making it to the top of the stack that ignite when they get the air. Any way to get more air into the firebox? More air and a bit smaller fire would probably mean more gets burned in the evap instead of outside your stack.

[802maple]

I think a smaller fire, fired more often will help you out, not so much heat and more air I still will solve your problem

[powerdub]

I would be thankful for stack fires. The draft they create is awesome and it rivals a boil with forced draft. I used to pray for stack fires before the forced draft. We fill the box as full as we can get it every three minutes or so, mostly soft wood (90%) as our hard wood for this year is almost gone. Getting 90 gph pretty regular out of the old 2.5 X8.

[802maple]

Hey Scott

Have you ever tried boiling with a lesser amount of wood. Ryan is getting about 100 gallons per hour and his grates are barely covered. I was just wondering.

[powerdub]

Yes and it seems to do better with a full wood box.

[802maple]

Like I said I was just wondering

[powerdub]

No problem, we have tried all kinds of things over the years like different levels of wood, different fan speeds, mixing serveral different types of wood, propane injection, wait, I haven't tried that one yet but it works for my pick up. Maybe next year, thanks for the idea.

[802maple]

Get a gasoline fuel injection system from a couple formula one cars and I bet that baby would boil, What do you think Russ you got anything like that hanging around down in the auto shop.

[Russell Lampron]

I do happen to have an the remains of an S-10 in the yard. I'm not sure if it is port fuel or throttle body. If it is port fuel Hmmm! I could be the first to have a fuel injected evaporator.

Russ

[Justin Turco]

Well, I agree with the build up of unburned gasses theory. But either way. I have just one thing to say. THAT IS COOL! I wish mine would do that!

[Three Saps Sugar Shack]

i get approx 65 gph evap rate burning all pine , on a 2.5x8 grimm lightning raised flue... no pre-heater, no forced draft... just an occasional stack fire... will try the less, more often firings... but every time you open a door... the boil nearly haults.. thats why i was trying to keep the firings minimal......as always your input is always welcome.. and thanks..,peter.

[802maple]

Don't open the door for long periods of time 4or 5 seconds and close it you shouldn't lose your boil