Cannot get syrup pan hot enough?

[Lazarus]

Just started up yesterday and have run about 300 gallons, but I just can't seem to get my syrup pan hot enough. This is a perpetual problem with my budget GBM 2x6. The front of the flue pan is flying but the syrup pan is just lazing along. Also, every time I just about get to drawoff, the temp suddenly slips 5 degrees and it takes three hours to get it back. This happened twice today. I finally drew off a whopping half gallon slowwwly and lost 5 degrees again. Wood is hickory and plenty dry. Draft door is open. Pans are running about an inch.

I had ths same problem last year. Is there something I'm missing or is it my evaporataor is just cheap?

-Laz

GBM 2x6
225 taps

[Dill]

What if you close the draft door? If the flue pan drop or raised?

[Ecnerwal]

If the same thing happened last year, it's presumably either the evaporator (or perhaps the arch under it) or how you are building/stoking the fire. I'll leave making detailed guesses about solutions to people with real evaporators...

[Lazarus]

7 inch drop flues. I've never actually run it with the door closed; however, closing it seems to make the temp drop.

[SevenCreeksSap]

So what do you do, finish off the evaporator? afer a test boil I'm wondering if I'll run into the same thing. It seemed like the back of the syrup and the front of the sap pan was going good, but front of syrup pan where the draw off is didnt boil quite as well. I guess building the fire evenly in the fire box might be the trick.

[killingworthmaple]

I have had this problem with a couple different evaporators over the years the one I have now is new to me this year and it had that problem. What I did was open the door while the fire is going good and take a good look at what the flame is doing, I found that the flame is racing past the front pan strait to the back. So a quick fix that works really good is too force the flame forward first then let it go to the back. I took a piece of heavy cast and made a shelf that comes forward from my back wall in the firebox and it fixed the problem. I boiled today and it boiled almost too good in the front pan. Hope that helps if you couldn't follow my line of thought give me a call and we can chat.

Nathan
860-604-8115

[MapleOak]

How often are you feeding the fire & what size logs are you using?

[Lazarus]

Feeding the fire about every 10 minutes. Wood is split small - smaller than you would use in your fireplace.

-Laz

[Maplebrook]

Lazarus,
Keep any cold draft off the front of the evaporator. When you load the wood, keep it to the front so the door will just close.
I had this problem with my evaporator and these two things helped a lot.
Darren

[Lazarus]

Thanks... any suggestions as to how far open the draft door should be?

[Brent]

As noted above a cold draft hitting the front of the pan will really slow down the boil. It sure does on ours. If the door
in the sugar shack is open and the wind blowing, the front pan does not work so well.
I think your 10 minute firing cycle is too long. Add wood more frequently in smaller batches.
Before we started messing with air over fire air injection, 6 minutes seemed ideal.
Also check the gasket between the pan and the arch. If you don't have a good seal there cold air
will get sucked in under the pan, cooling it. When it's cool in the moring, lift up the pan and look for tell-tale sign
of leaking air. Color changes in the soot around the edges on the bottom of the pan will guide you to the leaks.

It also sounds like there is too much under fire draft. You may have to settle for a slower overall boil by
restricting the draft a bit and avoid having too much heat going too far back too fast.

Do you have a stack thermometer. It is possible to tell from that
1) when to fire ... you see the stack temp drop
2) if the draft is too high. Temps at about 1100 should be a good target. If you start hitting 1400 or so
on a small rig, you are sending too much heat to far back and up the stack.

[Maplebrook]

Lazarus,
I read in another post where you are outside this year while your sugar camp in in transition. There is the problem. Any kind of shelter you can get around the your evaporator to protect it from the elements will make it work better.
My camp was 3-sided; I had to close in the open wall to see an improvement. Nice looking plans!
Darren

[Clarkfield Farms]

Page 1, Post #6 by killingworthmaple - am I the only one that read that? I completely agree with Nathan. An appropriate baffle redirecting the flame path will fix it. If you have a draft, it's likely hitting more than just the front of the syrup pan, so -- it's all about where the heat's going, not where it starts out. Just my two cents.

EDIT: oops, didn't see that you're boiling outside; still, redirecting the flame can only help. Is that four cents now? or am I in the hole?:confused:

[Lazarus]

Yes, I am outside this winter and it is really, really challenging. I'm under an overhang and only protected on one side. Yesterday the wind was blowing so hard that the steam wasn't even getting a foot off the pan before being whisked away. I hesitate to box it in, because this timber frame storage barn just got built, and cost more than my first house. I'm trying very hard not to damage the tongue and groove ceiling with the steam, just trying to get through the season until the new sugarhouse is built later this year. I did place a few sheets of plywood around me, but the roof is so high and the wind comes in over the plywood, so I'm not sure how much it helped. But last year I was fully inside another barn with no wind at all and had the exact same problem with the pans.

I did shut the draft door down to only be open about two inches, and that seemed to help. I had been propping it open wider (you can see that in the pics). Even so, it seemed at times it wanted more air, other times less.

I did always wonder what a stack thermometer was for, but that sounds like a great way to tell what the arch is doing. Is that just as simple as drilling a hole in the stack and popping it in? I'm running all single wall pipe since I'm outside - where is the best place on the pipe to mount it?

Here's a few pics of yesterday's fun. The first is a pic of the setup. The second is the rig going.


52025203

[Lazarus]

YeastPimp - Yes that was weird, I only saw Nathan's message in the thread just a minute before you posted. It's like it didn't show up right away for me.

This is a really good point though. I started out on a little Mason 2 x 3 a few years back and did exactly that - built a wall right before the stack exit. Of course, on a 2 x 3 the entire thing is a syrup pan, so that's the same thing as building a little wall behind the syrup pan. I guess on a ramped arch I didn't think to try that, but I can certainly fit some bricks in there at the start of the ramp. The flames are truly flying back along the flues when I open the door (although it's hard to tell if that's because I opened the door).

-Laz

[nymapleguy607]

It sounds like you have a little to much draft. I have had this problem with my 2x6 before, the flue pan boils really well, but the syrup pan suffers. I could never totally fix the problem on mine. I basically just tried to balance between the flue pan and the syrup pan. An easy way to adjust the draft would be to put a few fire brick under the base stack to reduce the air gap. this would lower your amount of draft.

[delta757and767pilot]

I think you should adjust the fire bricks hire so the heat is directed up. Take photos of your setup.

[wiam]

Get a good probe thermometer. I got mine from Condar. http://www.condar.com/probe_meters.html I like that it goes up to 1700. Leaders only goes to 1000 and it costs more. I run mine at 1400. Drill a hole at head height and stick it in.

[Dill]

I would go with the too much draft/ not enough baffle idea as well.

[Lazarus]

Ok, so here's my plan. I've ordered the Condar probe thermometer (Thanks William!), and I'm picking up a bunch of extra firebrick tomorrow to build a low wall between the syrup pan and the flue pan. This year I used 1" arch board as the first layer inside the arch then bricked it with half bricks, so it's already very tight in there near the stack where the ramp is highest, but I think I can close the gap significantly at the bottom of the ramp. I'll also continue to keep the draft door a little more closed than I have been. It's looking like huge sap days ahead, but I'm trying to hold off boiling until Friday when I can do a longer boil. I'll report back with the results!

-Laz

-Laz

[maple flats]

When I had a 2x3 1/2 pint I had a brick wall up to within 1" of the pan and I boiled outdoors, but the wind was generally blocked. It boiled good. I then made a simple hood with a 6" vent in the top and the boil got significantly better. That hood was just a rectangle, 8" high and a flat top with the 6" steam vent. To see inside I had to lift the hood (used a glove). When I graduated to a 2x6 I had my sugarhouse, but the bricking was similar. I had a wall up to within 10", sloped up and rearward until the brick just barely missed the drop flues. Everything boiled rapidly. How is your firebrick installed? I think that might be the issue.
You say your wood is split smaller than the fireplace. It should be split to about wrist size.

[Dill]

What about putting a sheet of plywood or 2 on the outside of your shelter? Keep more wind off of the evaporator. A hood on the pans would help as well. I boiled outside for 2 years, it has its challenges thats for sure.

[Daren]

Mine does the same thing. I started to fire through only one door and built the fire as close to the front as possible. When the door glows red, the syrup pan starts to look good. I have thought about putting a damper in the stack, but now my thinking is to mount a squrrel cage blower in the back of the arch angled on a 45 towards the top front of the arch. I can say that as little as building the fire as far forward made a nice improvement.

[Lazarus]

Hmmm. The fire is about as forward as I can get it. Most times I am pushing on the wood to close the door. I do tend to bake the paint off the door, but it's never approached a color change to red. I know I should probably put some plywood up - I have a few sheets strategically placed, but I don't want to nail anything into the new barn. I know it's silly, but it cost a fortune, it's brand new, and I don't want to scratch it (new car / barn syndrome). And it's only a temporary situation until the new shack goes up this year. I'll have to think about the hood idea. I have some sheet aluminum around here somewhere I could probably use.

Tonight I did build a small wall out of firebrick behind the fire box at the bottom of the ramp, and the stack thermometer came in the mail. I'm trying to hold off boiling until Friday, but will post an update and let you all know how it goes.

[Tucker08]

It seems as though draft is your issue. Too much of it. I have seen where people control flow by putting sand between the arch and the evaporator pan. This not only gets heat closer to that pan, but also keeps it in the fire box longer. Couple that with a blower, and you will see improvement. You will have to play with it because if you close it up too much and have a blower going you will have smoke in your face every time you stoke it. Also, the goal would be to run it with the doors closed, as open doors pull cold air across the top of the fire. Good luck.

[Dill]

If you don't want to nail, staple gun some cardboard or plastic up.

[jmayerl]

If you don't want to nail, staple gun some cardboard or plastic up. ditto on this idea, I stalled up cardboard and it helps a bit.

[Lazarus]

OK, I built my wall behind the syrup pan, the draft door is nearly closed, there is ZERO wind, my stack is 600 degrees, checked for leaks and re-leveleled all pans. And now, instead of lackluster boil in the syrup pan, I have almost no boil. The front channel is silent. Back two are a little bubbly. Flue pan still cranking.

So. Basically, a lot worse.

????

-Laz

[killingworthmaple]

I am wondering what does the flame look like when you crack open the door. Is the flame hitting the front pan. I had zero boil in the front pans then redirected the flame and have a very good boil. When I started I had a small wall in the back of the firebox. After remodeling it I had a wall with a shelf coming forward that makes the smoke and flame come forward 6 inches before it can start it's journey back to the flues. It works very well and is done all the time by wood stove manufactures that is where I stole the idea from. I can guarantee you if you have fire licking the bottom of the front pan it doesn't have any choice but boil.

[Indiana-Jones]

Lazarus, how many inches from the bottom of the front pan to the bottom of the fire box, do you have a grate?

Could or would it help to add more bricks so that the fire is closer to the front pan?

[RileySugarbush]

How about some photos or a little video tour. That might provide some info for someone here to help you out. You will be able to make it go!

[Lazarus]

The vertical distance between the grates and the bottom of the syrup pan is 18 inches. Is that a lot? I usually pile the wood as high as I can get it.

I will take some video on tomorrow's boil. My camera is making everything green since it's dark and I am outside. But definitely video tomorrow.

-Laz

[HHM-07]

Had that problem, you need to put a row of bricks at the front of your flue pan so you only have an inch or so of space between them and the bottom of your flues, that will hold the heat under your front pan it works good 4 me,

Good luck Dick

[Lazarus]

OK, I have some videos, and I am still working on posting them. In the meantime., I was quite surprised that my syrup pan actually started to boil this morning before the flue pan, and I am fairly pleased with with amount of boil in there. What I did differently today was keep the draft door open at its lowest notch, only an inch. I don't know how it's getting air, but it must be. The stack is relatively cool at about 400 degrees.

BTW, since last week's fiasco I drew everything off the evaporator and started fresh this week. After boiling 14 hours yesterday on new sap, the evap was really flying this morning and I got my first draw off a few hours in.

Now the bad part. Just like last weekend, I right after did my first drawoff, a very slow 1/2 gallon, the evaporator backed off 3-5 degrees, and has refused to budge since. It's holding steady, but now four hours after the first drawoff it has yet to move a single degree. So even though it seems to be running better, it's still not producing syrup. The pan is getting vey dark, too. I'm adding a drop of defoamer every time I fire, only at the float box entry. What the heck is this?

-Laz

[Peepers]

I'm no expert on flue plans and don't have a divided pan yet but the symptoms seem to all point at the flue pan evaporating faster than the front pan so the "almost syrup" is just trickling into the front pan and simmering away (getting darker) instead of finishing. It seems odd that the divided pan sitting right above the fire isn't rolling if the flue pan is going good. Is your arch setup like this Outdoorsman model: http://andersonsmaplesyrup.com/files/Outdoorsman.pdf? Seems like this design has quite a bit of space/angle from the fire box up towards the stack. The pictures don't look like they have any insulation on/around the door either.

I like Killingworthmaple's idea of building a wall and a shelf to force the exhaust forward before letting it hit the flues if that's possible on your rig. Then stoke it frequently and open the draft door. 400 degrees at the stack seems really low - I have small pans but get a wicked boil everywhere running 700+ on my block arch with a little 4' stack and natural draft.

[jfroe939]

No offense, but this seems borderline nuts. I've read 4 pages about all sorts of adjustments to make and nothing's been working for you when it should because the ideas are good and insightful. I made my own 2.5 x 6 and I don't have any problem getting the stack temp up past 1000 on just about any day except when the wind is wrecking havoc. There's guys on here using barrel arches and cut-out oil tanks... for sure a manufactured, name-brand 2X6 can make syrup or else it would be pulled off the market. So it's gotta be something unique to this particular situation that giving you fits.
If putting up cardboard or whatever to block the elements isn't working, then throw as much wood at it as you can. If that doesn't create a roaring flame, then open your front door 3 inches so we can determine that getting air isn't a problem. If the flame looks roaring but none of it's hitting the front pan then that means there's too much draft sucking heat out your stack, so put a damper in the stack. If you have it loaded full of wood and it's been burning for 15 minutes, but doesn't look roaring then maybe you don't have enough draft. Your unit is 6 feet long, so your stack should be at least 12 feet long. One of these things have to work. I mean, it's just burning wood, not rocket science. Make sure your wood is stacked high enough in the front so the flame has a chance of hitting the front pan, too. I'm super anxious to see video or pictures or something. Try getting stillshots from your video if you can't get the video posted. If you have a windows xp computer, open Windows movie maker and you can get stillshots of video if all you have is video; or use any movie-editting software on Windows 7 to get a stillshot. I guess I'm interested in seeing what kind of flame you've got going on. If the flames are roaring, there's no good reason why that setup couldn't pour some heat. Good luck. If your video is roughly under 15 mb, I'd consider downloading it and giving some input if you can't get it posted here.

.... I think I just found your pictures... I went back to the Evaporators forum and clicked on the paperclip attachment thing and there were 2 pictures. Looks like your stack is plenty long. That makes me think you "might" need a damper in your stack because it's sucking too much flame away from the front? Make sure your firebox is good and full of wood. I'd still like a picture/video of the flame somehow.

[Lazarus]

OK, sorry for the long delay in posting - too busy boiling! But, you are right, this is beyond borderline nuts. I got a new one for ya.

Twice in the past few weeks, as I was attempting shutdown, the evaporator kind of became possessed. The flue pan started to race flat, pushing sap up along the sides, which caused the float box to go quiet. The level dropped a little quickly and the syrup pan took off, I got two drawoffs 20 minutes apart. Crazy. It was good I was watching and was able to dump some sap into the float box to wake it up, or I could've had a major issue.

It happened the following day, too, only this time I was ready. Rather than have a panic, I just watched the level carefully to make sure it wasn't getting too low. It was like the evaporator suddenly woke up. So, trying to figure out what was different that happens during shutdown. The only answer I have is that I stop adding wood. In both cases, I only had about two inches of coals / leftover embers in the fire box on top of the grate.

So the other day I tried to run it like this. I only added one layer of wood on top of the grates and kept it hot, ading only 3-4 very small pieces of wood each fire. The flue pan ran kinda pokey, and the stack was so cold it barely moved the stack thermometer. But the syrup pan was screaming and I got regular drawoffs. The farther down the fire is from the syrup pan, the better it boils, not closer. I lose it if the fire box gets even half full. I went through a lot less wood this way, too, and less sugar sand buildup. Syrup is still a bit on the dark side, but I'm late in my season now.

So this makes no sense to me how three or four tiny pieces of firewood burning in a huge fire box doesn't go straight out the flue. But there you have it. That's apparently what it wanted!

-Laz

[Brent]

The hotest part of a flame is not close to the wood. It's up at the tips. When the box is half full I'll bet the flame goes up and bends back with the tips at or at least near the flue pan.