Question about firing

[heus]

I have read through here and see that with double doors you should fire on alternate sides and open just that door. On my 2x6, however, the left door must be opened before the right one will open. How do I fire alternately if that is the case? Do I just leave each door cracked open a little so they will both open when needed? I noticed in my test boil that the fire burned hotter and "louder" when the doors were shut tight and ash door open all the way.

[Hop Kiln Road]

We have three different generational "chiefs" running our 2X6 during heavy runs and we each run it differently and we get different results. There really isn't much effect to alternating loading doors on a 2X6 because the firebox is so small. My father-in-law disagrees. Read Scott Nearings book on sugaring in the forties if you have the chance and he talks quite a bit on different operational techniques and the resulting syrup quality. Bruce

[Russell Lampron]

Like Bruce said the firebox is small on a 2x6. I open both doors on mine to fire. Open doors, toss in hand full of wood, slam doors shut and repeat in 5 to 8 minutes. I try to get this all done in 5 seconds. Sometimes it takes longer but never more than 10 seconds. Having the wood pre selected and ready is the key. The longer the doors are open the cooler the front pan gets.

[heus]

Thanks guys. How much wood do you actually put in the firebox? For example, do you just want a couple of pieces over the grates, or just enough to be burned in 5-8 minutes?

[KenWP]

I would say that you put enough wood to keep the fire hot but not to much that you waste wood. I try to put wood in front each time and then push back with a stick before adding more. That way I have the fresh wood burning and the really hot stuff at the back. Seems to work. I do also try to lay wood the other way also to get a sort of open flow going. I only burn cedar and some spruce so it disolves quick.

[3rdgen.maple]

Hues why can you not just open either door? Mine bound a little in the middle so I took a grinder and touched them up and can open either one first. I do fire with only opening one door and you can notice the difference as how much you kill the boil with only one door open compared to both. But like already said if you fire fast and often you are not gonna hurt your progress much if any. Once you get some hours on that rig you will find out what works best for you. I try to keep the firebox 2/3 full.

[PerryW]

I like to open it quick and chuck a couple pieces in and slam the door quick. My wife likes to load it up to the brim. Either way works.

[Father & Son]

When you fire, cris cross each layer of wood that gives air space between pieces of wood for better burning. Also don't load the firebox higher than the tops of the doors. This gives airspace between the wood and the bottom of the pan for combustion. Consistancy is important, alot of people use egg timers to fire. Once you run your new rig for a few hours you'll find out how long it takes for the wood to burn down so you just add one layer each time you fire. Hope this helps.

Jim

[Hop Kiln Road]

What you're trying to acheive is a consistant, even, uninterrupted boil, which is more of a challenge on smaller evaporators. The drawoff takes even more experience. There was another thread discussing drawoffs recently. A 2X6 doesn't have much gradient push so if you are new to the evaporator, start off slow...or you'll be half asleep wondering why there are big, dark bubbles in the middle of the pan but the drawoff therometer only says 216! Bruce

[Russell Lampron]

Before I had the blower on my evaporator I used to try to keep the firebox about 1/2 full. It burned the hottest that way. With the blower I need to just about fill it to get some burn time.

[Hop Kiln Road]

Hi Russ! I thought you were making more time between firings so you could take Miss Ruby for a spin in the doddlebug! Bruce

[Brent]

If you get a real hot fire you'll likely need to grind the doors, until you insulate them. My doors get glowing dull red and I had to grind to compensate for the greater expansion of the doors compared to the frame. Plan to insulate this year. I never load much past half way up, and I had some air injection above the fire. Not high pressure but it made a difference. If you load to the top I think you'll be starving a lot of the wood gasses of oxygen and while it may be hot, it will be less efficient and cost you more wood.

[Amber Gold]

Russ, if you weren't pushing 1000cfm of air through your firebox you're burn times might be a bit longer. You're blowers about twice as big as mine.

Heus, fire in one shot...both sides at once.

[peacemaker]

because like said the firebox is small in a 2x6 i use a bottom layer of bigger pieces and a top of small splits and pallet wood i fire one door most times maybe every 5 or so i open the other to set a new base = the door under my drawoff side stays shut

[WESTVIRGINIAMAPLER]

I fill my firebox about full every 10 minutes. I have tried everything and it evaporates the best when the firebox is full. Either way, uses about the same amount of wood as you would add about the same amount either time to get the level back up whether you are filling it 1/2, 2/3 or full with as my blower pushes about 750 cfm.

[red maples]

2x6 firebox is small and you need to criss cross fire fast each layer alternate which way it goes each time you fire. and with the patric design the firebox is fairly tall I think so like 3rd gen said you need to keep it about 2/3 full.

I need experience with it too. but when I test fired I only opened 1 door the right why? Idunno and that was all I needed to get the wood in. that baby gets hot definitly need gloves...mine were in the house. I also insulated my doors that helps keep the doors cooler!!!

[heus]

What you're trying to acheive is a consistant, even, uninterrupted boil, which is more of a challenge on smaller evaporators. The drawoff takes even more experience. There was another thread discussing drawoffs recently. A 2X6 doesn't have much gradient push so if you are new to the evaporator, start off slow...or you'll be half asleep wondering why there are big, dark bubbles in the middle of the pan but the drawoff therometer only says 216! Bruce

Bruce,
What would cause it to make syrup in the middle of the pan?

[PerryW]

heus,

Some reasons why syrup may develop in the middle of the pan:

- uneven firing, (like a hot spot in the middle)

- intermixing of the pan sections when you are boiling hard

- after startup or after reversing the flow or the evaporator

[Russell Lampron]

Bruce I get the boiling done fast so that there is plenty of time for Doodlebug rides with Miss Ruby. She likes to watch the sap climb the ladder.

Josh I have a damper in the blower that is choking off more alot of the air flow. I can adjust it so that I can leave it on when I fire. Having too much and being able to fine tune it is better than not having enough.

[maple flats]

I fill 1 door at a time and fill it to about 3/4 up on the door. I criss cross the wood (slant one layer left and next layer right and then 1 straight, keep alternating) which gets more air thru to burn faster. I keep the draft door full open. This is in the past. This year I will have under and over fire high pressure air. According to what I read I will fill slightly higher and burn down farther each cycle. My cycles were every 5 minutes and I expect maybe 15 this year if the report I am going by is close for my size evaporator. No matter how you fire it the key is split small and use dry wood. If it is not dry you waste wood just evaporating the water in the wood before any real gain on temperature can happen in the firebox. If your wood is not dry it will need to do for this year but your first matter to attend to for next year is the wood. I used to be short and always had to use unseasoned later in the season, now I have about 2 years ahead and it makes a big difference. As for 1 door or both at once, just try each way, maybe 1 door at a time one boil and both doors the next boil. Whichever you do, have the wood right there ready to put in as soon as you open the door, not even a few feet away. Door open time is lost hard boil time. I set my next load to go in right next to the fire door, off to one side, where I can grab it fast. After I close the doors, set my timer for next fill and check the pans I refill the pile for next firing. There will never be a dull moment, you will be very busy and having the time of your life all at the same time.

[Hop Kiln Road]

heus -

I just heard Brad Gillilan from Leader speak on "Consistency is the Key to Making High Quality Maple Syrup." He was very good. He says that all problems in the syrup pan are the result of the an unaddressed problem in the flue pan 20 minutes earlier. He said we should strive to run the evaporator so there is a consistent draw of syrup: if your unit does 4 gallons an hour you should be drawing 8.5 ounces a minute. Obviously, the smaller the unit the harder it is to achieve.

So when I get syrup in the middle of the syrup pan, it is a result of losing my gradient. Surprisingly, loss of the gradient in the syrup pan is usually caused by over foaming in the flue pan. When the flue pan foams up, the foam actually slows the evaporation and traps more gas in the boiling liquid, which expands the boiling liquid and fools the float into thinking there is more sap in the flue pan than is actually there. Then when you refire and the boil subsides the float suddenly lets a lot of sap in and this charge of 2% sap suddenly entering the flue pan interrupts the gradient and the 8% sap exiting the flue pan into the syrup pan and and creates a below density section as it flows across the syrup pan eventually trapping syrup behind it.

A lot more to his talk about how to fire and how to set the floats. But he wants no foam whatsoever in the flue pan. Fire a 2X6 every 5 to 8 minutes and then add defoamer to the flue pan float box.

Bruce

[Hop Kiln Road]

Russ - Yes you are faster and have a better looking ride and that is why I get stuck with her sister Ms Onyx. Last time we danced, her niter stockings took the skin off one of my shins! Bruce

[heus]

heus -

A lot more to his talk about how to fire and how to set the floats. But he wants no foam whatsoever in the flue pan. Fire a 2X6 every 5 to 8 minutes and then add defoamer to the flue pan float box.

Bruce

Bruce,
Thanks for the explanation. So i should make it a habit to put defoamer in the flue pan float every time I fire?

[WESTVIRGINIAMAPLER]

Another thing that will cause you to make syrup in the center section is an evaporator that is off level a little too. Don't take much as the syrup doesn't like to run uphill.

I speak from experience,

[Hop Kiln Road]

Heus - Just checked my notes. Stack temp at eye level 700 - 800 for grate air; 830 - 950 for forced air. Use stack temp to determine firing sequence but should run 5 to 8 minutes. Wants air space all around the fire so wood should be 2.5" from the door in a 2X6. 1 or 2 drops of defoamer in the float box every time you fire sometimes more for late season sap. Bruce

[Amber Gold]

Russ, true just giving you a hard time about the size of your blower on your 2x6. I got the mainline today and will see you in the morning.

[Amber Gold]

Bruce, I didn't see you at Bellows Falls today. Dill and I showed up late after we made a trip to Bascom's and only caught a part of Brad's talk. Did those stack temp notes come from Brad's talk? I was getting 14-1600F last year and will be rebricking the back part of the arch to close things up a bit and hopefully bring those down. I was having lots of problems last year losing gradient and making syrup in the middle. I'm thinking it was likely a function of inconsistent firing and poor wood quality. The wood quality is fixed this year and I hopefully will get better at firing. The season's coming up fast.

[heus]

What happens if I do make syrup in the middle of the pan? Do I attempt to scoop some out and pour it near the drawoff?

[3rdgen.maple]

Hues I have not made syrup in my middle chamber. If by some odd reasons it does a couple things you can do. Remember the bucket of fresh sap by the evaporator for emergency. Time to use it. It does not take long to start burning the pans up at this point. Or you can use a scoop and add some raw sap in a hurry. I think if you try to draw it off by the time you get it into the front chamber it will not be flowing out the drawoff fast enough to stop disater from happening. By the way I only add a couple drops of defoamer about every hour. The way I see it is I am drawing off on average 1 gallon an hour so every hour I add and have not had any foaming problems.

[danno]

Heus - Just checked my notes. Stack temp at eye level 700 - 800 for grate air; 830 - 950 for forced air. Use stack temp to determine firing sequence but should run 5 to 8 minutes. Wants air space all around the fire so wood should be 2.5" from the door in a 2X6. 1 or 2 drops of defoamer in the float box every time you fire sometimes more for late season sap. Bruce


Real good info here Bruce. I would really like to hear Brad speak on the topic. Were those internal or external stack temps?

And for those considering scooping raw sap into the center channel to thin syrup made in that channel, I can't remember why, but doesn't this cause a pan scortch? Wish I had temp guages in each channel.

[Russell Lampron]

Bruce it is true that the ladies love my ride. I haven't met one yet that didn't.

I add defoamer on a regular basis and it does make a big difference in the evaporation rate. I normally have no foam in the flue pan and by keeping it under control back there have very little in front pan.

Over flooding your front pan at shut down and inconsistent firing are a couple of things that will make syrup in the middle of the pan. Late season sap will do it too.

[Russell Lampron]

If I start making syrup in the middle of the pan I draw off about a 1/2 gallon at the side that I am drawing off from and pour it into the 3rd channel back from the draw off. I keep doing this until I get the sap moving in the proper direction. Keep an eye on the bubbles this is your clue. If you start to get big ones in the middle start the process it normally doesn't take long to get things straightened out. If you wait too long to get things moving dump some raw sap into the in coming float box and open the firebox doors to get things cooled down.

[Hop Kiln Road]

Those stack numbers are Gillilan's, internal, at eye level. And these guys are serious about the firing sequence timing: they use an egg timer! Like Russ just said, they said no foam whatsoever in the flue pan. None.

Amber Gold, he was actually talking about have MORE airspace under the flue pan than less in a forced draft (but non over air fire) evaporator and more air space around the actual fire. This allows more oxygen (from the under fire blower) to mix with the fire and gases under the flue pan. The Force 5 I saw run the other month had a stack temperature of only 650 degrees. But I suspect in that application, over fire air, gas combustion takes place earlier and the heat stream under some portion of the flue pan is baffled and the exhaust velocity slowed before it reaches the stack.

Gillilan was not a fan of a mixing solution in the syrup pan when syrup developed in the middle of the pan. He said to put a drop (one) of defoamer in the end of the channel by the draw off box and a drop (one) of defoamer at the top of the second channel, draw off slowly, and the syrup will come off !!!! Incidently, he said he uses an auto draw off but puts a ball valve ahead of it and only cracks the first valve so when the auto opens the syrup comes off slowly. Another guy there, who draws 100 gallons an hour, draws a small stream continiously, too.

[maple flats]

I heard Brads talk 2 years ago, and I used his method last season. It did make a difference. I never had syrup in the middle. I fired every 5 minutes using a timer and added 1 drop of defoamer every 2nd fueling. I have tried to do continuous draw since I heard a talk by Glen Goodrich a few years ago, but never achieve a true continuous draw. When I can draw for 15 minutes or more I consider it an achievement, often times it is only 5-10. I would expect to get it after I invest in an RO (hopefully 2011 season) because the infeed will be much higher % to start and production will be several times more/hr. Right now I typically get about 5-6 qts an hr, sometimes 7 or 8 if the sugar is high that day. But it is too hard to throttle a 3/4" ball valve down slow enough to hit it exactly right. I do now use Brads wood fill suggestion, criss cross the wood, for better air penetration. I think it was his talk that covered the topic of flames out the stack. If you see any flames it is not flames straight thru but unburnt gasses getting oxygen and re igniting. If you see flames there add more air. (I think this would be a good case for over fire air injection)

[WESTVIRGINIAMAPLER]

Leader should have a new arch for sale likely by this fall and it is supposed to be a lot cheaper than an Intens-o-fire or Force 5. The air is high pressure damper controlled and it swirls above the fire. Be interesting to see how it performs compared to the others. Supposed to use less wood also. They have been testing it for 2 or 3 years and should have some good numbers after this season.

Brad is a great guy and very knowledgeable and helpful. Definitely one of the brightest young guys in the industry.

[Amber Gold]

Bruce, isn't the rule of thumb 1" air gap below the flues? What distance did Brad state?

[Brent]

Last year I had low pressure air injected from 2 tubes above the fire and felt like it helped.

After reading an article, I think from Michigan Forestry, they tested and found even the temperature of the air being blown into the fire made a difference. This makes sense. The more cold stuff that goes in and has to be heated to combustion temperatures, the lower the the efficiency. I never got around to trying to take hot air from the ceiling or around the stack but I did play with wood temperature. Stack temp is just one thing to watch.

Here is how I found another. I had a helper one day and stepped outside to do something while he was firing. The stack belched black smoke. Hmmmm why is it so black ? Normally I don't see any black smoke. Two stacks emitting steam from the hoods and the smoke stack had always been clear. So I watched more an noted that when he fired, there was about 2 minutes of black smoke then it went clear ... and stack temps were higher. So we tried firing more frequently with smaller piles of wood. We also made a sort of wood preheater ... we stacked the wood in front of the evaporator doors where the radiation, and there was lots of it, preheated at least one side of the wood.

By firing in smaller batches and with somewhat pre-heated wood, we got more consistent stack temp ( internal near 950 - 1050) and less black smoke and for shorter times. Black smoke = lower stack temp.

Not very scientific but we got great boil rates from a little 2 x 6. If I get the blower system upgraded this year as planned, the intake will be from next to the stack at the roof level. The air there is nearly 80 degrees and the air on the floor of the shack is barely above freezing, and that cold air is what is going in the draft under the fire.

[Hop Kiln Road]

Josh - He said no higher than the top of the loading doors.

Brent - I have a buddy who is a woodsmoke chicken b-b-q champion. He also preheats his wood prior to load in order to maintain a constant temp in the smoker when he refires.

Bruce

[heus]

Hues why can you not just open either door? Mine bound a little in the middle so I took a grinder and touched them up and can open either one first. I do fire with only opening one door and you can notice the difference as how much you kill the boil with only one door open compared to both. But like already said if you fire fast and often you are not gonna hurt your progress much if any. Once you get some hours on that rig you will find out what works best for you. I try to keep the firebox 2/3 full.

3rdgen,
I noticed today that I can open the left door first if I want. I guess it just expanded, so like you said I will have to grind some of the middle edges.

[3rdgen.maple]

Hues Patrick did forewarn me that I might have to when he delivered it. I went with his suggestion which was to do it when they are hot and binding so you do not remove more than necessary.

[dano2840]

i was wondering about the black smoke, i ran my 3x8 as hard as possable and i did have flames going staight up the stack, if you opened the flue clean out doors it would come staight at you and make a violent 90 up the stack, when i fired i got real thick black smoke out of the stack for about 2 min also, on of my friends was driving by and the next day in school asked if i was burning tires, i happened to be into a part of the wood pile that was only slab wood that day, but i assured him i wasnt, he said there was a black collumn going up into the air probably 25 feet before the wind swept it away, i know i was over firing ( every ones been there, too much sap, boiling for 10 hours, your mentality is MORE WOOD MORE FIRE = I GET SLEEP FASTER) i had a little blower about 2 times the size of your fist, it couldnt run the evap with the draft door closed on its own but i would leave the draft open full and point the blower at the greats and it seamed to make a difference, im working on finding a blower big enough to run forced draft with the draft door closed. Iteresting thread here

[dano2840]

Hues I have not made syrup in my middle chamber. If by some odd reasons it does a couple things you can do. Remember the bucket of fresh sap by the evaporator for emergency. Time to use it. It does not take long to start burning the pans up at this point. Or you can use a scoop and add some raw sap in a hurry. I think if you try to draw it off by the time you get it into the front chamber it will not be flowing out the drawoff fast enough to stop disater from happening. By the way I only add a couple drops of defoamer about every hour. The way I see it is I am drawing off on average 1 gallon an hour so every hour I add and have not had any foaming problems.
just remembered the only time i have done that is when my rig wasnt level, i check it every day, if its not level i will have 3 of the 4 channels come to syrup at the same time, as soon as i got it level it runs just like it should

[WESTVIRGINIAMAPLER]

just remembered the only time i have done that is when my rig wasnt level, i check it every day, if its not level i will have 3 of the 4 channels come to syrup at the same time, as soon as i got it level it runs just like it should

Only time I ever had a problem either.

[clafarr]

I have experienced this "black smoke" The fire man is pushing the wood towards the flues,plugging the air flow to the smoke stack.A warning sign i have noticed is a "woofing sound" and then a loud bang from the smoke stack.
Your right about the tires. I was asked the same thing. If i could burn them I would.