Leaking front flues

[markcasper]

My Leader drop flue pan has suddenly developed the dribbles. Its 14 years old, never missed a year. There are at least 6 flues wet in the front end. Two of them are just plain unacceptable. Its in the very front and bottom of the flues. It drips real good from those 2 after the fire dies out, so I have been pouring 6-8 cups of filter aid down inside after the boiling subsides each time I shut down. That cuts the leaking way down until the next time. There is only going to be one or maybe two more fireups this year. After the filter aid treatment, the most it ever leaked out in 2 days of sitting idle was 1/2 a 9x13 cake pan.

I had a guy helping me fire this year and maybe he jarred them with wood, am not sure as I made it aware to him to "don't hit the flues".

My question is can this be fixed?? I hate to have to by a new pan especially since I have to spend 1000's on new tubing for next year. The pan was made in 1998 and is soldered. Enough information.

The rest of the flues are in fine shape, no pin holes, etc....

[DrTimPerkins]

...My question is can this be fixed?? I hate to have to by a new pan especially since I have to spend 1000's on new tubing for next year. The pan was made in 1998 and is soldered. Enough information.

Most likely either the sap boiled out of that area just long enough to melt the solder, or they got hit with wood. It happens.

They can be trimmed back (if necessary) and resoldered. I'd check around and see if someone out there can do it before bringing them all the way back to Vermont. You may be able to do it yourself.

[Homestead Maple]

Radiator stop leak might help you git buy untill you can git it solderderd.

[DrTimPerkins]

Radiator stop leak might help you git buy untill you can git it solderderd.

That product is definitely not food-grade.

[Jeff E]

Mark, that sucks.

Maybe ask Pete Roth if he knows who can help. I will check around up here for you.

Curious, DE must 'bugger up' your syrup pan pretty quick?

[RileySugarbush]

That product is definitely not food-grade.

Turns your syrup into Keopectate .......

[PerryW]

yes it can be fixed. it just needs resoldering. I was able to fix my front (stainless/soldered) pan with a propane torch and lead-free plumbing solder & flux.

[markcasper]

Thanks fellas for the encouragement! It is ok for this year. I had no plans of doing anything other than what I have been doing. (I heard a story a while back of corn meal flour working really well as stop leak.

The DE doesn't seem to be affecting anything. I'll have to say.....this has been the best year in dealing with sugar sand....there has not been hardly any. My Marcland valve used to start clogging up after about 300 gallons. So far it plugged up only once.

From what I hear, not many people are eager to tackle a syrup pan, yet alone a flue pan because of the difficulty in soldering due to sugar sand deposits.

[mapleack]

Mark, it's not that hard to give solder repair a shot. The most important thing is clean clean clean. I've found that a brass cup brush in a drill works best. Use it on the areas that are leaking until they shine. The second important step is liquid flux for stainless. I like stay clean http://www.harrisproductsgroup.com/en/Products/Alloys/Soldering/Fluxes/Stay-Clean-Liquid-Flux.aspxi or lennox brand liquid flux. Lastly, the best tool to have is an old fashioned soldering iron that you heat up with a torch. For what you need to do I'd say one that is about an inch in diameter and three inches long would be best. Heat it up and use it to melt the solder on. If you try just using a torch on the pan there's a good chance you'll only melt out solder thats still solid on the pan by getting it too hot. It also helps to have two irons so one can be heating while you're using the other. Good luck.

[Sugarmaker]

I think Andy is right on the mark! Good luck and this is something you can do yourself.
Chris

[WESTVIRGINIAMAPLER]

If you are not comfortable fixing it and have a Leader dealer within reasonable distance take the pan to him and have him take it with him to Leader the next time he goes and if he is going to stay overnight which he would likely from Wisconsin, they could probably have it fixed by time he left if he was there a while and they knew it was coming and were ready for it or he could pick it up the next time he went back to Leader. Better to get on it now so it will be ready well in advance of next season.

[Haynes Forest Products]

Mark Get Jim Shumacher to give a quote on a copy of the pan he is doing some nice remakes.

[markcasper]

I will have to consider all options and decide. There is a metal fabrication guy within 15 miles from me, my brother has taken many farm items there for him to fix and he does do excellent work. I just don't know if he is into soldering. Is the pan that I have soldered deep down the inside of the flues? If thats the case, then there is probably no hope.

I am curious as to how long a stainless pan is expected to last. If it doesn't get hit with wood, doesn't run dry and is always pulled up from the ashes at the end, then it should practically last past a lifetime?

On a different note, I was looking through the Leader catalog of a few weeks back and noticed they have joined the "reduce your carbon output" group in advertising the vortex wood-fired evaporator. Is not burning wood carbon-neutral and thus would be a bit of false advertising?

[talahi maple products]

I was able to stop a couple leaks in my flue pan with small stainless steel screws and copper washers, they held good and now that I've got the pan off and cleaned up for the year they still look good. :)

[maplecrest]

one old trick that worked for years here with my old 4x12 drop flue rig. was to cut a felt filter in strips. push the strips in the flues with yard stick where leaking. will swell and stop leaks. need to be pulled out when cleaning at end of season. that worked for many years. could not see fixing the flues to be hit again by wood.will leak for a few minutes till seal.

[markcasper]

How big of holes did the felt strips plug? Are you talking the orlon filters cut into strips? I have a real big problem now! I failed to do anything about this when I should have. There were 8 flues that had hard deposits of niter and/or burnt syrup packed in the bottom front of the flues. 3 of them had probably a 2" X 1" deposit, the other ones were a bit less. Last spring when i finished up there were 3 leaking, but would quit once the fire got hot enough. I imagine the heat was burning the sap and sealed it off until it cooled down. The deposits were rock hard and ended up grinding 2 electric fence posts, one into a chiseled point, the other into a wedge. I took and prodded very carefully these areas until all of the crap broke loose.
One flue has a hole in the very front and bottom and I can almost get my pinky through it. I am taking it to a machine shop Monday and see if they can do anything with it. Alot of the fronts of the flues have some rust on them (exterior)and I am wondering if the metal burned and now is rusting. I called about getting new pans and I guess I am SOL on that one....too late.
Does anybody have any pointers as to what to do now? or any ideas I can tell the fabricator?

Can someone tell me why a few of the drop flue fronts look like they are buldging, like maybe 1'' high and 2'' back in on the bottoms? Is this a standard thing to have happen on drops because of the heat?

[Potters3]

I have seen bulging flues from freezing hard before. Not sure if this is what caused yours.

I would be very careful who I let fix this pan, it should have many years left in it if fixed right. Leader had fixed the old pans I us to boil on and did a great job.(luckily only a 45 min ride ) we had full sap tanks and a leaking pan they fixed it will we waited. But if done wrong you can end up ruining a pan. i have been told NEVER use a torch it is too much heat everywhere and can melt soldier from all joints. If you take it somewhere make sure they have done this kind of work before. Check with a leader dealer out that way, hopefully they can stear you toward a good repair place, or arrange trucking back to vermont.

[red maples]

I know a friend that has a drop flue with forced air and his was somewhat old welded pans maybe 10 ish not sure. and from the extreme heat over the years with the force air it basically eventually just wore the front of the flues out. they thinned out he tried to get new caps welded to the front but the welds didn't hold (possible too thick and over heated???) anyway he eventually broke down and purchased and set of pans well slightly used anyway, for this up coming season. The front of those flues get very hot as you can tell from the boiling rate in the front of the pan. there is alot of heat abuse than can over time break down the metal. that is why the new hurcane force 5's can't be made with dropflues becasue the extreme heat combined with the air turbulance just destroys the front of the flues!!! They tried wrapping them with ceramic insulation and re capped with metal they still failed.

I am sure you will figure something out. at worst case senario see if you can find a custom metal fabrication shop they may be able to weld new caps on the front flues depending on damage. one test you might wanna try is warm/ hot water with red food die or something in it just to see exactly where the leaks are occuring. then you can get a better assesment of the damage!

[maplecrest]

Mark, to answer your question,1 is youir rig oil or wood fired? 2 i found out the hard way that you cannot let sap freeze in stainless steel flue pans.my guess that is your buldging problem. the old english tin pans could take freezing solid and slowly thawing out with no problem. my first set of stainless flues i let freeze. did not know better.they bludged and started to leak. i used felt filter cut into large strips and folded to jam into flue that swelled and sugared over to stop leaks. i used that same pan for many years till went to oil fired.for it to work the holes need to be towards the flue pan ends. if in middle of flue channel will not work the felt will move.how i found this works was one year i had a neighbor who wanted to help. he opened the fire box door and thru the wood against the flues causing one to leak.having a felt strainer right there and a knife i cut a strip and took a yard stick and pushed up against the leaking flue. sealing it for years.i did pull them out to clean the pan in the spring. on thing i will say. we only made 500 gallons of syrup at that time. do not know about larger scale production doing this.i gave up on drop flues when i added the r/o.

[DrTimPerkins]

There were 8 flues that had hard deposits of niter and/or burnt syrup packed in the bottom front of the flues. 3 of them had probably a 2" X 1" deposit, the other ones were a bit less.

Sounds like the problem was caused by excessive niter build-up. Once the pan surface is completed covered with niter, the boiling liquid doesn't contact the metal any longer, thus it will overheat to the point where the solder melts. If anything, the DE probably made it worse in those areas. This problem more frequently occurs in the thin deep flues of a backpan, but you can run into a similar problem even with welded pans in extreme cases. If you get too much niter built-up in an area, you'll develop a hot-spot and the pan will warp in that area....makes like a small 1-4" circular depression. Do it enough and your pan looks like the surface of the moon, and you'll never get it completely level again and always have hot/cold sections and run into scorching issues unless you run it real deep from then on. See attached image. Very sad to see a pan get to a point like that.

As others have said, find somebody who knows how to do a solder repair (with an iron, not a torch). After that, clean the niter from your pans more frequently.
5020

[Jeff E]

OK Maplecrest, you have me wondering, why abandon the drop flues when using and RO?

[maplecrest]

was out drawing the flue pan. had to shut guns off to catch up. when float came back up fired guns again.had float set for all it could take. tryed taking float out.now leader has since changed to deeper-larger float boxes. but the 6 to 8 inch deep by 16 inches long box was not enough to keep a 6x10 drop flue with enough sap to keep up with what i was drawing off.in short that set up was not designed for consentrate sap.no problem with my cross flows and raised flue set up now.went from a 6x14 leader to a 5x13 lapierre and make the same amount per hour.at 15%

[Amber Gold]

Jeff, I thought it was acceptable to let the pan's freeze, figuring the sap would expand up, not out, due to the path of least resistance. It must be a PITA having drain out a large rig like yours when we get hard freezes early season. Do you dump the sap into a tank in the SH? Doesn't the tank freeze and what do you do with it then? Just wondering how you do things. I'd be hosed if I busted my flue pan as the season was starting up. Last season was the first year I let the sap freeze in my pans. It got pretty cold, but I don't recall if it froze solid.

[SSFLLC]

Hi Josh, We always put a 100 watt light on under the pans when its going to be sub freezing weather out. I believe that its better safe than sorry. I think Brad (Red Maples) also puts a light under his. Keith

[Jeff E]

Jeff, I thought it was acceptable to let the pan's freeze, figuring the sap would expand up, not out, due to the path of least resistance. It must be a PITA having drain out a large rig like yours when we get hard freezes early season. Do you dump the sap into a tank in the SH? Doesn't the tank freeze and what do you do with it then? Just wondering how you do things. I'd be hosed if I busted my flue pan as the season was starting up. Last season was the first year I let the sap freeze in my pans. It got pretty cold, but I don't recall if it froze solid.

The question goes to Mark Casper, but I was in the same boat when I processed outside on my 2x8. When it froze at night, I drained my pans and took 'sweet' into the garage, to keep it from freezing up. Lost the gradient in the evaporator and it made dark syrup for several hours when I re-fired.

[markcasper]

My rig is wood fired, 14 years of use, average6- 700 gallons a season, last year was 1000. I have had sap freeze in the pans before, I usually put a milk house heater or hotplate in the arch if it gets too cold. All of the flues are not bowed out, just a handful of them. As Dr. Perkins said, I am thinking niter in the flues started this. I never boiled concentrate until three years ago and that maybe is what got this started.
I appreciate everyones knowledge and experiences! It is a bit scary hearing a few of the responses. Worst case is I give it up this year. Half of my taps are out for this year as our woods got thinned and they just got done and will not be able to get a whole lot back in within six weeks.

I will make some phone calls right now.

[Jeff E]

Sorry to hear about the grief Mark. Thinning the woods will pay of though, good move on letting those maples crown out a bit!
Good luck with the evaporator.

Cooking on a conventional pan set with concentrated sap definately has its challanges. My flue pan looks like my front pan used to look, nitred up.
The front pan is on a reversing rotation right away, every 40 gallons of syrup or so. I have had trouble, as maple crest has described, especially when switching sides when I get a big draw off. back pan cant feed fast enough. I have been flooding the back pan prior to switching, that helped push more sap forward. I have resorted to dumping sap into the front pan...that was a bad day.

[maplecrest]

josh i now drain my flue pan every nite. i have a 80 gallon tank in back of rig, i wash my flue pan every day.i generally boil 6 hours between washing. boil 3hours change front pans boil 3 more shut down and clean. if i have alot of sap i just rinse the mud out of the flue pan. rinse the front pans and boil another 3 hours.i generally get a 5 gallon pail of mud out of my flue pan every day.i have had the sap in tank freeze but not solid. but it did move the sides of the tank out.

[Amber Gold]

With as big as you are, I'm amazed you have the time to clean you're rig that often. 5 gallons is a lot of crud and I can see why you do it so much.

[DrTimPerkins]

...As Dr. Perkins said, I am thinking niter in the flues started this. I never boiled concentrate until three years ago and that maybe is what got this started.

That's a good point that people don't often think about. When you switch from sap to concentrate (say 8%), you'll probably notice that the niter builds up faster.....and it is. With concentrate, you not only have concentrated sugar, but concentrated minerals in the sap. The concentrate is 4x the amount of sugar, so processing 10 gallons of concentrate is like processing 40 gallons of sap in terms of niter formation, so you're also making syrup 4x faster and also making niter 4x faster. You need to clean more frequently and switch sides more often.

[markcasper]

Good analysis in the former post Dr.Perkins. Another problem I believe and correct me if I am wrong.
The solder in the lower portions of the front flues eventually gets worn away from use, minor leaking started occurring which formed into a charcoal mass on the inner flues, which causes the metal to overheat, melting more solder and more leaking and then you get rust from the burned metal and a resulting hole in the flue.. It is a dirty shame because the rest of the flue pan is in perfect shape for being 15 years old. Even after the pan was 5 years old, I remember seeing a weeping flue here or there, but would mostly be gone after the first boil.