Evaporator Problems

[Amber Gold]

Still new to running an evaporator so I’m not sure if it’s something I’m doing or if it’s the evaporator, but things don’t seem to be operating as well as I think they should. Started boiling yesterday about 12:30 and stopped at about 9:30 and had only boiled 250-275 gallons, which yields an average evaporation rate of about 30 gph, half of what I think it should be.

I have a 2.5x8 with blower and forced draft grates and burning split slab pine. Kept it fired about every 5 min. throwing a couple of sticks in. When I fire I typically get a good boil in the front pan and maintain a rocket type boil for the first 12+ inches of the flue pan and it tapers off from there. I took a 1.5 hour break to install lights, but had help firing the evaporator…wasn’t a rocking boil, but it was least boiling during this time. I’ve read up on the posts that talk about this so I think I’m doing everything right. Even with the 1.5 hour break I think I would've at least average 45-50 gph.

Also I’m when I draw off I’m starting heavy and go slightly light. I notice that my temperature gauge spikes 227 +/- for a while when I’m drawing off and then will settle back down. So I’m making syrup in the 3rd channel. When I’m drawing off it’s slightly light 56 brix or so at 190 degrees and will have a gradient in the pan. Will wait a 20-30 minutes, check density and see that it went down (not reading) and notice I’m losing my gradient. By the time it comes back up to density on the drawoff the last 3 channels have the same color (no color gradient) and the first channel (where the sap’s coming in) is getting a caramel color. When I drawoff I go through having the temp spike and finishing slightly less than syrup and going through the process again. Also, when I drawoff it’s coming in 1-1.5 gal draws. Not sure what it should be for my size rig, but that seems like a lot. I just reread the making syrup in the middle channel thread and will try adding defoamer in the drawoff channel to see if that helps.

My main concern is my evaporation rate. I’ve still got 550 gal of sap I was supposed to get through yesterday and don’t want to go through the season averaging 30 gph.

Thoughts??

Thanks

[partsrus1974]

what kind of preheater do you have?Also how big and how long is your smoke stack?Do you have a 5'.5" flu pan?I think you should be doing 50gph

[Amber Gold]

No preheater. Stack is 14" (stock size) and is 15' long. 5.5' flue pan.

Just spoke to someone and said I may be getting too much air. Hadn't thought of that...thought more air the better. Blower's mounted on a switch, but am going to mount it on a speed control and see if regulating it will help.

[Dill]

Can you get more of a boil in the flue pan without the blower? Or at least get a rolling boil the whole length?

[Amber Gold]

Haven't tried operating without the blower. Probably should've tried it yesterday. Wish I had time tonight to boil, but I'll need to go home and plow. Trying to leave work early tomorrow so I can boil.

I'm getting a rolling boil the full length now, just not rocketing out the full length. Only rocketing out the first 12" or so.

[RileySugarbush]

Try just restricting the blower inlet instead of a speed control. Quick and easy.

But before you cut the blower back, think about where the heat is coming from. If you think you have too much air, the other way to think about that is you don't have enough fuel. You described your firing a couple of sticks every 5 minutes. On my 2x6, I load a good armful of hardwood every 5 to 6 minutes. By your description of the boil, I bet you don't have a big enough fire going. What is your stack temp? I'm guessing it is low.

More power, Scotty!

[Amber Gold]

Don't have a stack gauge, yet. Maybe I should get one.

I'm throwing in 3 wrist/fist size wood about 20"-24" every 5 min.

[Dill]

More wood! You have more wood than you have time to boil right? Now's the time to use it. Fill 'er up!

[RileySugarbush]

That's not near enough fuel, especially pine Try two to three times that amount and make sure it is crossed so you get good air flow.

A bigger, more consistent fire may help with your syrup pan troubles, too!

[danno]

Josh -

I have tried all the go fast tricks and I have never been able to obtain great evaporation rates either.

On my 30x8 I was hoping for 50, but could never do much more than 35 - and that was with 550 cfm forced air, relatively air tight arch, 18' of stack, preheater, good wood, frequent loading, etc.

On my 3x10 I was hopeing for 100 gph, but it is closer to 85 gph when I'm pushing it.

I hear these guys doing 85 gph on a 3x8 and I just don't get it.

Also, I make syrup very much like you do - very few draws, but when they come, they are big. Usually middle of the draw is like 225-226, sometimes 228-229 (yikes). I've tried the defoamer trick but have not seen any change. I've tried to start the draw earlier like at 219 or 220, but when I do that, I stay too thin and don't hit the higher temps. Go figure?

[Amber Gold]

I don't mind puttin' the wood to it, butu I'm not sure how I could fit more wood into it. I keep it just about up to the bottom of the pan. Haven't tried criss-crossing...maybe that will help it burn hotter/faster so I'll go through more wood.

Draft doesn't seem to be a problem. I leave the blower on the whole time and never shut it off, even when firing.

[RileySugarbush]

Now that is totally strange! If I open my firing door with the blower on I lose my eyebrows! Something else is going on, that pine should be ripping hot like a forge when you open the door.

Somehow, the whole combustion process is getting choked off. Since the blower isn't blasting out the door, that means you have a very open draft under the pans, which doesn't seem to be the case in your photos. So it must be the incoming air.

Blower too small? ( I have a 200CFM on a 2x6)

Grate openings too small?

Do you have a bed of coals on the grate?

[Amber Gold]

Using 30" forced draft grates, no coal base to speak of. There's some, but not much. Not sure what the cfm is. Where do I find the CFM rating of the blower? The blower came off a 2.5x6.5 Grimm with the same size stack.

To me the fire's ripping, but I have nothing to compare it to. Never actually looked in the firebox when it was running and the evap's I've seen when running all have hoods on them so I'm describing what I think is a good boil. Again nothing to compare it to. I think having geysers of sap shooting out is a good thing and when everything's fired at my peak that's at the first 12" of the flue pan wth a rolling boil the rest.

Thanks for the help.

[3rdgen.maple]

Amber Gold that is a pretty low number for that evaporator. Im getting 40 gallons an hour on a 2x6 with no blower. What depth are you running your pans at? I do know that there are some days that no matter what you do things just don't boil good. Barometric pressure or something like that. Run that rig again before you make any dramatic changes could of just been one of those days. Also I know when the sugarhouse doors are open the breeze blows right throught the door and smacks the evaporator in the face I can actually here the boil slow down when someone opens the door. So I keep that door closed. Hope this helps.

[Amber Gold]

Yesterday was my first day at an extended boil period to see what my evaporation numbers really are. I run my pans as low as my float allows; 1" in the front and 1.75" in the back. I can't run them any lower. It was windy earlier in the, but that died down with no apparent change in evaporation judging by boil in the pans. Doors are closed on the sugar house.

Just ordered the speed control. Hopefully can leave work before they close so I'll have it for tomorrow.

[3rdgen.maple]

Just thinking a little maybe a little too much but are the fireside of your flues clean? I clean them before every boil. If the soot builds up or plugs them maybe it is restricting the fire. Good luck with it. Be sure too let us know how everything works out.

[tapper]

Josh,
I am running a 30 x 8 leader drop flue with airtight arch blower and preheater. I try to keep the firebox no more than 3/4 full.
The blower is 980 cfm and came with a rheostat. I normally run the blower 1/2 to 3/4 speed and it is a very bad idea to open the door with fan on. I have to wait a bit to open door after fan is turned off. I average 75 gph and on a good day have seen over 100 gph.
Is your wood cured and dry? I get my wood a year in advance and keep it under roof although I have burend very wet frozen wood and still see 70 gph.

[Amber Gold]

I brushed them off before I started the season. Not spotless, but got everything I could off.I can clean them again and see what I get.

Thanks

[Amber Gold]

Tapper,

I like those numbers!

Most of the wood is dry...occasionally I'll find a green piece. I thought at first it was going to be a bad idea to open doors while loading and never had flame come out. Once I get it running right I probably won't be able to do that again.

[RileySugarbush]

Based on the latest discussion, I really think your blower is undersized. With the blower in the system, it becomes a limit on air flow and may even slow things down compared to an open draft door.

If you want to see what would happen with a bigger blower, replace it with a leaf blower for a few minutes and stand back! Even a cheap one puts out 300 to 400cfm at higher pressure ( and higher noise!) than a squirrel cage blower.

And go get a stack thermometer. The magnetic ones are cheap and available lot's of places. I bet you are down to under 400°F at the stack base.

[Amber Gold]

Will look tonight for a cfm rating. What should it be for a 2.5x8? If the blower's undersized can I run it with the blower and draft door open or will the blower just push air out the draft door?

Ordered the stack thermometer and it might be in tomorrow, if not definitely Wednesday. 3" probe, 1700 degree max rating, and I think made by flue guard or Condar. How far up the stack to I install it?

One time when I had a good boil going, the flue pan started to foam up bad so I turned the blower off and it died almost immediately. Not sure if this means anything.

[Dill]

Josh, I really have limited experience with blowers. I mean I just started playing with it this weekend. But it seemed like the boil was much better if I shut down the blower for a bit and let the coals build up and then turn it on. Just a couple of minutes between loading and turning the blower on.

[Hop Kiln Road]

Josh - Didn't I see in your pictures that you bricked the end of firebox vertically instead of ramping it up toward the flues? I think the concept of the firebrick ramp in the back of the arch is to direction the flame into the length of the pan flues. Bruce

[danno]

I just got out the "steam away" advertisement where they have the average evap rates for different size pans - for a 30 x 8 it ranges from 42 gph with a 4' foot flue pan to 55 gph with a 5.5 flue pan.

It's hot, but I'm able to fire with my forced air on and I'm blowing 1650 cfm - 1100 under the fire and 550 over the fire. The heat is going up and toward the stack, not out the door. I have to add defoamer to the flue pan about every 45 minutes.

I see my 3 x 10 is only rated for 78 gph. I can do slightly better than that - but I sure would like to see Tapper fire. Never mind - I just saw Tapper's pics. He has a 30x8 on steroids.

[Amber Gold]

Just checked on my blower and I couldn't find a CFM rating on it. Looked everywhere on it. What I could find on the motor tag is it's a 1/20 hp motor and 1.8 amps. I'm not sure, but I'm guessing it's the standard blower that comes with the 30" wide Woodsaver package.

Bruce, from what I understood before I bricked it the newer evap's are bricked with a vertical wall in the back so I bricked mine the same. I'll get a real good boil in the first 12" of the flue pan and then it dies off. I'm not positive, but I could see the ramp/wall in the back having some effect on the evaporation rate, say 5 gph, but I don't know about 30+ gph.

[WESTVIRGINIAMAPLER]

Just be patient and take some of these tips and work on it. Rome wasn't built in a day and things take time to get things worked out. You lost a lot with shutting down for 1.5 hours, lot more than you think. I started out with 35 gph on my 2x8 stock and now it runs 60 to 65 gph with a 5' flue pan. I run my blower wide open and it is 745 cfm and when the rehostat is cranked all the way down to fire it, it is still all the air you can handle and it is still nearly burning you unless you drop to a knee and keep the head low.

I tried on Saturday during the middle of the day taking out the rehostat and wiring up a switch and the fan didn't run nearly as fast and the boil and fire was nearly killed when I fired. Needless to say, this didn't last long, but was a good learning experience as I like to try different things.

Lowes carries a 5 amp fan speed control for $ 9.99 and worth the money. I would guess your fan will run a lot faster with the speed control vs a switch.

I am hoping that adding air all around the top of the fire will maybe get my rig to 70gph, but we'll see.

[WESTVIRGINIAMAPLER]

FYI My blower is 3.86 amps on 110 or half of that on 220. It is a Dayton Squirrel cage with a PSC(permanent split capacitor) with 745 cfm.

[danno]

Just be patient and take some of these tips and work on it. Rome wasn't built in a day and things take time to get things worked out. You lost a lot with shutting down for 1.5 hours, lot more than you think. I started out with 35 gph on my 2x8 stock and now it runs 60 to 65 gph with a 5' flue pan. I run my blower wide open and it is 745 cfm and when the rehostat is cranked all the way down to fire it, it is still all the air you can handle and it is still nearly burning you unless you drop to a knee and keep the head low.

I tried on Saturday during the middle of the day taking out the rehostat and wiring up a switch and the fan didn't run nearly as fast and the boil and fire was nearly killed when I fired. Needless to say, this didn't last long, but was a good learning experience as I like to try different things.

Lowes carries a 5 amp fan speed control for $ 9.99 and worth the money. I would guess your fan will run a lot faster with the speed control vs a switch.

I am hoping that adding air all around the top of the fire will maybe get my rig to 70gph, but we'll see.

Brandon - I added air above the fire this year and the jury is still out with the results. But, so far what I have seen is - same evap rate, lower stack temp, better wood efficiency, little ash in the fire box, very little smoke/spark out the stack.

[RileySugarbush]

Here is the description of my Dayton blower:

Blower,200 CFM,115 V
Shaded Pole Blower, Air Flow @ 0.000 Inch Static Pressure 200 CFM, Speed 1400 , Voltage Rating 115 Volts, Current Rating 2.10 Amps, Frequency 60/50 Hertz

It's hard to compare just on hp or current because some blowers are set up to run efficiently with high restrictions and others can't handle it.

But I think I could run better if I had a slightly bigger blower on my 24" wide arch and what I have is a bit higher capacity than what you have.

[tuckermtn]

Josh and I have the same evaporator pans- my arch is stock- no blower...from start up to shut dow this afternoon- 2 3/4 hrs- I pushed though 115 gals. of sap. so I'm averaging 42 gph- so I figure when its running full tilt I'm in the 50-55gph range. So even if Josh's blower is too small he should be getting quite a bit more GPH...but it seems like most of the things I would think of have been covered...not sure whats happening...

[Amber Gold]

Thanks for all the help. Jury is still out if I"ll be able to leave work early, but will be boiling tonight regardless. Still have 550 gallons to go boil and whatever I collect today.

Why would the speed controller allow the blower to reach higher speeds? Wouldn't a switch give it full juice and let run wide open? I picked up the speed controller this morning and will install it today and experiment with different blower speeds.

Brandon, during the 1.5 hour period my wife was manning the evaporator. She was keeping it at a boil, just not as good of one, so it was still doing something.

[Amber Gold]

Just spoke to Leader and his conclusion is the blower isn't putting enough air out. He said the blower should be big enough at 300-350 CFM at full speed and when it's switch mounted it's either full power or completely off. He's not sure if there's something wrong with the motor, but his conclusion is not enough air.

I guess for now I'll run it naturally aspirated until I can tinker with the blower and/or get a new one.

Thanks for your help.

[Dill]

You want to try my dump blower and see if it helps? (I'm serious).
Not sure what the cfm is but it will help narrow down the cause.

[Amber Gold]

Alden, wouldn't hurt. DO you know how many CFM's it is? Curious.

A friend of mine stopped over last night and gave me a hand. He's gotten things so they're running better, but not where it should be. We ran it without the blower and was able to get a hotter fire, better boil in the flue pan (about 18" of it now), build a gradient in the syrup pan and getting better drawoffs. We ran it without the blower. He said I wasn't going through wood as fast as I should be and my stack temps (going by feel without the gauge) aren't as high as they should be. He wasn't sure why. He said I should be gettting a good hard "talking" boil through 2/3 - 3/4 of the flue pan and I wasn't.

When I put the blower on I sealed the bottom with a piece of sheet metal. This is correct isn't it? You need the bottom sealed so all the air goes through the grates?

I'm working from home this morning and will be boiling this afternoon and tonight to try and catch up. I'm going to run it without the blower because so far that's working the best. Should I remove the bottom sheet metal to try and get more draft now that I'm running it naturally?

Stack thermometer should be in today so I can put that in. Should that be around 1000-1200 degrees?

When I bricked my arch I built a vertical wall up to the arch rails 12" into the flue pan and kept it at the arch rails till the last 8-12" of the flue pan and ramped it back down.

[WESTVIRGINIAMAPLER]

Besides blower, only thing I can think of is how the heat is directed around the flue pan. Might have too much ramp at the rear, but likely not if your stack is not very warm. Get a 700 to 1000 cfm blower and put on it and whamo, look out. Leader sells their 2.5 x 8 evaporators with a 960 cfm blower on it.

[Amber Gold]

I currently have a vertical wall behind 12" into the flue pan up to the rails with no ramp. I'm thinking this weekend I'm going to put a ramp in. Something quick and dirty. The back wall is bricked and mortared with vermiculite behind it so I don't want to take the time remove now. I'm thinking of taking a piece of sheet metal and laying it from the back of the grates and have it rest on the vertical wall forming a ramp. Do you think the sheet metal will hold up for the season? No weight on it, just flame. Not sure if I have the time to brick it up properly...currently buried in sap.

[DS Maple]

I would certainly recommend a ramp. You'll want it to be able to hold something though so that when you add wood, you can push the burning pieces up the ramp closer to the bottom of the flue pan. This should help you achieve a more rapid boil across the length of the pan.

[Mark-NH]

Josh,

Just confirmed through Leader that you are supposed to have 15-18" between the front of the flue pan and the first ramp and second ramp and back of the flue pan.

I think you may have restricted your draft path in the back judging from your photo bucket.

I have done the same with mine and have to move the ramps more towards the middle. Could not get abouve 350 stack temp so far.

[WESTVIRGINIAMAPLER]

Heavy piece of sheet metal would hold up the entire season other than a little warped if you wante to try that. Not sure the vertical wall is the problem as that is how the Intens-O-fire arches are developed but hopefully someone with more knowledge than me can chip in some more info.

[michelle32]

Make sure you have two inches under your pan or you won't have enough room for the increased pressure from the blower.

[Amber Gold]

Thanks Mark. I can dismantle the top row of bricks and probably get the sheet metal to drop in at 15-18". 350 is pretty low, I bet I'm about the same. Stack doesn't seem very hot. I'm going to loosen the sheet metal plate on the bottom to try and get more draft through there for this week. It looks like this weekend I'll be taking things apart and making some changes. Mark, are you saying that both ramps should peak 15-18" from the ends of the flue pan? I think I was 12" into the front and I think I was 12" from the back, but I don't recall.

I guess I could get some bricks and just lay them in over the sheet metal. I may have enough leftover vermiculite to support the sheet metal. Just go with whole bricks and worry about cutting them after the seasons over.

[Mark-NH]

I think that is exactly what I am going to do. Cut my steel baffles out, they are only tack welded in place, and make baffles out of brick for now. I don't think slope is a huge issue. The air tight arches indeed are flat faced.

[danno]

When we are talking stack temps - are we talking internal or external? Makes a big differance. Some of us are using the magnetic external that won't get as hot. Others are using the internal probe type. When you're talking over 1000 f., I assume we are talking internal.

[HHM-07]

Just a thought a friend of mine go a new rig last year with the same problem found out they wired the blower wrong was going backwards , i can't belive you can open your door with the fan going

hope you find the problem soon Dick

[Amber Gold]

Dick, there's air blowing out. Would it still blow air if it was running backwards? It sure feels like theirs air blowing out. I use it to get the fire going quick. I can swap the wires tomorrow and see if it makes a difference.

If swapping the blower doesn't make a difference I'm going to be tearing it apart and hopefully back together Friday night. Good luck Mark. Let me know how it works out.

Ran it all day today and averaged about 33 gph. marginally better.

Danno, I think it's 1000 internal.

[Hop Kiln Road]

Josh - My 2x6 is doing in the middle 30's gph on 15 minute wood loadings. External stack 375, internal stack 575. The new arch design that you have copied uses 11" flues. It is not so much the size of the fire as it's shape and direction. You need a ramp to direct the flame tongue in an arc the length of your flue pan. Bruce

[Russell Lampron]

I was pushing 50gph last night with my 2x6. I don't have a blower. The space between the top of the ramp and the front of the pan flue pan is 18" and my ramp at the back is about 12".

I think the piece of metal would warp too much. Try to make it so that you can cover it with bricks.

[Amber Gold]

Russ, After I wrote that that's what I was thinking too.

Thanks Bruce. When I rebrick it I'm going with ramps. It makes sense to have ramps...gives the flame a smooth transition to the flues.

[RileySugarbush]

Josh,

If you are not sure there is air blowing out then there is definitely a problem with the blower system. Even with a cold and empty arch I don't like to open the door with the blower on! It blows ashes in my face.

For the little it is worth, I have an opinion regarding the ramp.....

The angle on the ramp has little to do with how the gases flows up into your flues. More important is the amount of flow area there is to get the gases to flow into them. If your back wall is too close to the front that it does not leave much of the flues open , then the firebox is too short, and maybe you should move it back, (or tilt it back) to open up the bottom of your flues more. But it is the area, not the angle, affects that. Note Brandon's comment on the intens-o-fires being built.

Earlier in this thread there was a comment that with a blower you needed more open pathways. I think the opposite is true. With a blower forcing the draft, you can afford to have more tightly constricting passageways because you are not relying on natural draft to pull the air through. The smaller gaps improve heat transfer to the pans.

I wouldn't change your arch until I tried a higher flow blower, even with a temporary setup like the leaf blower suggested earlier.

[Amber Gold]

John, the blower is definitely blowing air out. I'm just not sure if it'll blow some air if it's spinning backwards and more air spinning forward.

I ran it all day yesterday using natural draft and lowered the sheet metal plate on the bottom to try and get more draft. I was able to average 33 gph, which is slightly better. I think if things were running properly I should at least be up to 55 gph running stock. My evap has a 14" stack and 15' of pipe so I don't think I'm restricted there. The only thing I can come up with it's getting choked down at either the front and rear ramp, or both.

In my photobucket page in the bricking pics I have a baffle in the middle of the raised portion of the arch. What's the purpose of it?

[RileySugarbush]

Josh,

If you have a squirrel cage blower, most small ones are driven by shaded pole motors which I believe will turn the same direction regardless which way the wires are connected.
You should be able to see if the fan is turning the right way. The the exit of the blower housing comes off tangent to the outside of the blower. Look at the cage turning and imagine if it is throwing the air out the exit. Since it is a centrifugal fan, it will blow some air for inside to out regardless of direction, but be terribly inefficient if run backwards.

Take a look at this wikipedia entry in your spare time!!!

http://en.wikipedia.org/wiki/Centrifugal_fan


It looks like your arch was set up for a drop flue pan and the baffles make it work for raised by forcing the flow up into your flues. How big a gap did you leave between the vermiculite and the bottom of the pan?

[maple-Q]

You can read that , but sorry , it's only available in french.

http://www.mapaq.gouv.qc.ca/NR/rdonlyres/35B6779E-F5EB-4A76-8B75-BA4F69A81039/17698/Partie3Questionnementetessaihotteetprchauffeur.pdf

[KenWP]

Ah somebody else from Quebec for a change.

[Mark-NH]

Josh,

Pulled the rear baffle/ramp out of my arch last night and it made a huge difference for me. My stack temp doubled and I had a roiling boil almost all the way to the back.

I "think" we were processing about 80 gph once we got up and running.

[Amber Gold]

I called up Leader and talked with someone over there about bricking.

This is what he said:

Brick the first ramp, the flat area, and the front face of the first (entry) baffle.
Brick the bottom and sides between the baffle
Brick the front face of the second baffle
Brick the bottom and sides behind the baffle to the back of the arch

Beyond the fire box I can use arch board in place of brick. He said to leave the back side of the baffles exposed.

If the baffles weren’t there and I was just using an entrance ramp and exit ramp, with the blower I should have 18” at the front and 14” at the rear. Without the blower it would be 15” and 12”. He said with a blower you actually need more space at the front and rear of the pan to push the air through. I told him that my evaporator’s running better without the blower and he said it’s because the blower can’t push enough air through. It looks like tomorrow night I’ll be tearing it apart. I’m going to use arch board past the fire box, because it’s cheaper and quicker, no brick cutting and mortaring required. Will arch board stand up to direct flame long term?

Mark, does your evaporator have a baffle in the middle of the raised section of the arch? Is that what you pulled out? So are you just coming up with the entry ramp and then dropping right back down to the floor of the arch so you have no filler after the entry ramp?

John, nice link. I had my wife turn the fan on and it is spinning the right direction. I brought the vermiculite up to the bottom of the rails. The bottom of the flues is 1/2"-1" above that.

[WESTVIRGINIAMAPLER]

Ok, for reference, I can do 65gph on a 2x8 with 5' flue pan and only 8 flues and all the air I have underneath the fire is aprox 20 holes give or take a couple that are only 3/4" in diameter thru a full size firebrick and I went from 50 gph with stanard Leader woodfired grates which had several times the air spacing that these 20 small holes do to 60 to 65 gph with these small holes. By the time I got done drilling all the holes, I would guess my masonary bit was worn down some to the point the holes were less than 3/4".

My point is that if anyone other than Jerry Masterson had told me to due this, I would have thought there were a little crazy but when Jerry tells you something will work and work better, then it will work. I have 4 rows of 3 firebrick running lengthwise in the arch and no holes in the front firebrick and only 1 hole in the rear firebrick and this creates nozzles that cause it to roar. I have a 745 cfm permanent split capacitor Dayton blower and with the fan speed control turned down, you can hardly fire it but this is good as I get almost instant ignition of the new wood as I fire every 10 minutes and I hardly lose any boil. If the blower was on high, it would be impossible to fire. With my Leader inferno front, it has aprox 6 or 7 half inch nozzles injecting fire all around outside of the archfront and also air injecting on inside of door frame for cooling.

My evaporator may do a touch better with a high pressure blower, but this blower is pushing air so hard that not nearly the air can get thru it can push but it creates pressure and it pressurizes the arch good. Less is better, it is in the quality of the air and how it is coming into the arch.

[Amber Gold]

I tried one last thing tonight before I rebrick my arch and it didn't make things any better, maybe slightly worse. I knocked down most of the wall in back and put a slope to it, now the entrance and exit of the pan is in the same vicinity as the two baffles. Not sure what's going on, but tomorrow I take it apart and rebrick as Leader said to. I hope that works. Norman was able to find the original owners manual for it and it says to brick it the same as what Leader said.

How many feet of stack should I have? I have a 5 or 6 foot base stack with 10' of stack. It's also 14" in dia. Not sure if this would make a difference, but the stack is 4' from the cupola and is just slightly shorter than it.

I've gone through almost 3 chord of wood to make about 15 gallons of syrup, talk about inefficient.

[KenWP]

Your useing 3 times the estimated wood the experts tell me you would need.

[Amber Gold]

That's what I'm thinking...

[PerryW]

Total Stack length is usually twice the length of the evaporator, so your stack length sounds right.

My 3x10 has 20' of 15" dia. stack just for reference.

[WESTVIRGINIAMAPLER]

If your blower isn't putting out nearly enough air, then your stack needs to be above the coupla to help pull proper draft. The coupla has to be affecting it pulling draft as the blower apparently isn't doing much of anything other than hurting you. The top of the stack needs to be above everything so it doesn't have any restrictions. If you had another section of stack, this is what you should have tried to start with.

[Russell Lampron]

Josh I thought that Stuart told you that you weren't using enough wood! It looks like the opposite is true. I hope that rebricking fixes it for you.

[Amber Gold]

Just checked the stack in it's about 6" below the peak of the cupola. Not sure how much of a difference it would make. The stack is off to the side of the cupola, it's not directly in line with it. My stack is 10' section of spiral seamed HVAC pipe, not sure what I'd use to extend it. If my stack thermometer would ever come in I'd at least have that for a reference.

Russ, with the amount of hours I've put into boiling though I should have gone through over twice as much sap and I be able to keep ahead of it. Boiling 1.8% at 30 gph is almost like watching paint dry. It takes a long time between draws.

[KenWP]

Even a length of sheet metal wrapped up to make a pipe would let you get higher then the cuopla.

[Grade "A"]

I am passing on what a heating man told me, he said you need your stack 2' above the peak of you roof. I don't know if it will help but thats what he said.

[WESTVIRGINIAMAPLER]

You should be able to find a section of 10" pipe at a hardware store or somewhere in a scrap yard. If you blower was pushing 700 to 800 cfm, then this is not much of an issue but with your blower not working correctly, you need that stack at least a foot above the coupla and 2 or 3 feet would be better. I can almost guarantee you that you are shooting yourself in the foot with the stack below the coupla and it won't get much better until you extend it above the coupla or put a blower on it that will push a ton more air.

[Amber Gold]

I spoke to Leader again and asked him more questions.

I'm burning dry slab pine and he said with all the flat sides it reduces air flow through the wood so may be limiting the heat of my fire. I do split the slab pine down to 3-4" widths. After I rebrick it, I'll start with the slab pine and if that doesn't work then I'm going to mix in some hardwood from my home heating wood pile and see if that makes a difference.

I asked him about the blower and he said if it's running up to speed it's plenty big enough.

Also asked him about the stack and he said that should be fine, even with it being adjacent to, and the same elevation as, the cupola. If rebricking doesn't work, I'll run down the to the hardware store and grab a sheet of sheet metal.

I'm trying to take things one step at a time so I can narrow down what the actual problem is.

[RileySugarbush]

I stopped by the sugarhouse today. Your comment that you could fire with the blower on was bugging me.

Here is a test you could do to see if your blower is putting out as much air as mine:

Cold arch, stack open if you have a damper. I don't.

Stick some paper towel over the door and turn on the blower. Mine was standing out like a flag.

See photos

[WESTVIRGINIAMAPLER]

Josh,

I'm no expert but if you are burning dry slab pine split to 3 to 4 inches, you should be able to run 50 to 60 gph stock with no blower. You should almost need a damper to hold that thing down and I would think it would easily run 1200+ internal stack temps with no blower or higher.

That is like rocket fuel.

I think I had mentioned before that the same blower Leader installs on an arch that size is 960 cfm.

[RileySugarbush]

and 960cfm would blow that paper towel to shreds!

[michelle32]

I don't know if this could be the problem. But maybe your greats are upside down.

[Amber Gold]

I modified the arch per instructions and it did run better, although not 60 gph. Still not getting most of the pan at a rocketing boil. Slab pine is dry, some is damp because I coverd it with tarps and you can never keep everything out. I did run it for a while selecting just completely dry wood and it ran marginally better. I split all pieces to 3-4". I agree should be like rocket fuel. Looking at the fire it looks like it's drafting plenty good.

I ran it all day today with the blower on. I don't like changing it mid-boil becuase there's a lag time between when it runs good one way vs. the other. I'll run it all day tomorrow naturally and see how it goes.

[3rdgen.maple]

Amber gold All I use for wood is slabwood also. I Get a hard boil from one end of the pan to the other end. The only problem is it burns up fast. How much better did get after the arch mods? Seems like you have covered everything possible. Do you have a spark arrestor on the end of your pipe? Pipe plugged with a racoon lol? I know one year I had birds build a nest in my chimney on the house.

[Amber Gold]

If I kept at it I'd say upper 30 gph. The rocketing boil is now in the middle although it's not quite as intense as it was before and the rest of the pan has a rolling boil, with a dead spot in the back. I had people stop over 3-4 times yesterday so I got distracted a couple of times, but never lost the boil.

I have forced draft grates so they only go in one way.

What length wood should I be using? The grates are 30" long. I started off cutting wood at 18" lengths and thought it was too short so about half my wood is 18" and the rest is 20-22". I"m thinking my wood should be 30" long. It looks like I'm going to run out of wood so I'll be able to cut some more and find out.

[KenWP]

Dumb idea but if you cut it to fit your fire box side ways instead of length ways you could load it two directions and increas the surface area to burn and also to increase air flow. Remember the way we were taught to start a fire with wood running both ways. Works well burning also.

[WESTVIRGINIAMAPLER]

If you have forced air grates, then you are not going to be able to pull enough natural draft to get sufficent boil and the blower you are running is not putting enough air in the fire. If you could install a 600 to 900 cfm blower, you will see a big difference.

I know I stated before that the Leader & Grimm 2.5 x 8 evaporators come stock with a 960 cfm blower on it, at least they did a couple of years ago and regardless of what Leader tells you, if a 300 cfm blower would work, why would they spend the extra $$$$$$ to put a blower on that costs 3 times as much, because it is neccessary. I don't know that you have to run it wide open, but I bet if you were pushing about 750 cfm per hour, you boil rate would be at least 60 gph. I push a 745 blower wide open on my 2x8 which is significantly less surface area than yours and can do 65 gph and this includes STARTUP AND SHUTDOWN and with pine 3 to 4 inch slabwood, I think I could run 70 to 75gph.

[Amber Gold]

For the first couple of hours I tried the evap. out yesterday with natural draft and couldn't get it boil very good so I turned the blower on. I tried out some different firing techniques and found somethings that really helped out. My average wood length is about 18-20", I think it's too short. I started stacking the wood in two deep and that got a better fire going. I also made it a point when I fill one side to stir up the wood on the other. Once I started doing those two things there was a noticeable difference in the fire. Things got much hotter and I was seeing flame in the gap between the flue pan and the collar. Also I had a wall of flame coming out of the back of the fire box into the flue pan which I never had before. Things are coming together and working better. Not sure what my evaporation rate was becase I spent the first 2-3 not doing much under natural draft, but it's definitely a lot better. I think the biggest thing holding me back now is the wood. 90% is dry pine, except it was tarp covered and still got damp. I'll need to find a better way to cover the wood this year.

John, I did your blower test and it wouldn't put it straight out at 90 degrees, more like 75.

The blower may be to small, but I'm not going to worry about it this year. I'll probably be putting blower/air injection system in that was discussed in a previous thread adn will need a new blower anyways.

Thanks for everybody's help.