Variable result in 3/16 lines

[tgormley358]

It's my first y ear with tubing and i'm trying to figure why so much variation in the output between lines. I'm putting around 50 taps on tubing this year, mostly 5/16, but yesterday i ran 2 new lines of 3/16 where i have at least 20' of drop, maybe 25. At least half of the drop is on the last 50' of lines that are only 125-150' long. Each line has 7-9 taps, they're right next to each other, very similar trees and sun. I don't use any mains, just run these into collection tanks at the bottom. Using the same spouts and connectors, and tubing, i got very different results, and I'm guessing its something i did differently in my installation. Comparing the two lines, I got 3 times the sap in one line vs. the other during the first 12-hour span. I have one theory to ask about, but looking for other ideas / explanations.

The only difference i could see in my installation of the two lines is on the one that is running 3x faster i started tapping at the top of the line (first tree), while on the 2nd line i started tapping from the bottom (last tree). I'm wondering if this affected the vacuum somehow in the 2nd line which isn't running as well. In this, i could remove the taps and re-install starting from the top and see what happens. Do you think this is worthwhile? What other differences could explain such a big difference between the two lines?

[SeanD]

It's not your tapping order. At least, I've never heard of that.

If all things are equal - slope, tubing, fittings, number of taps then I think your options are either a leak, the quality of the tap holes, or just different trees.

If it's a leak, you might see little trains of air bubbles running down the line. You might even hear the hissing. If it's the tap holes, it could be the quality of the wood or the side of the tree. Maybe north-side holes are just getting going while east or south-side holes are drying up. Or it could just be the trees themselves. Some trees just outperform others.

[tgormley358]

Alright, i'm going to go look for bubbles, and might pull and re-install some taps in the 2nd line and see what happens. I drilled my tap holes "straight in" vs. angled up, on the recommendation of a more experienced friend and mentor who has 300 taps in town.

[buckeye gold]

Being new to tubing I don't have a lot of experience to draw from, but I saw this happen among my lines this year. I had one that for every intent and purpose was just like the others and I was always disappointed when i went to it's collection tank. I walked it a couple times and saw no leaks and could not figure out what was different. Then one day I walked it and ran my hand along the line as I went and bingo I found a leak right at a tree. I guess a squirrel at just bit into it enough to puncture a hole, but left a flap that had turned against the tree and looked normal. when I pulled on the line it would open up and make bubbles, i could even hear it. when I had big runs I didn't have time to walk lines, so I did not see what was happening. when flows picked up the extra weight and vacuum would open the hole and kill my flow right there. My sap was at a stand still almost. So look really close you may find a hidden leak or a loose Tee

[DrTimPerkins]

Most likely leaks or plugs at fittings. Tapping order shouldn't matter, unless you stopped partway through tapping to drill a hole in some metal or a rock with your tapping bit.

[drewlamb]

Major vac leaks on 3/16 will usually cause sap in the line to race quickly down slope downstream of the leak due to air pressure from the leak. Often a line with a big vac leak will look to have no sap in it at all, or just a thin bit of sap running down the bottom of the line with air on top. If the slow lines are full of sap and just not moving much, my bet is you have a plug in one or more of your Ts. These are easy to find. Start somewhere in the middle of your line and pull a spout. If sap rushes out from upstream, there is not plug toward that end. Halve the distance downhill toward the end of the line and check again, and so on. When you pull a spout that sap is not running out of, you know the plug is somewhere upstream of that point. For me, plugs almost always occur in the hook connector that links to the saddle on the mainline, so I actually usually start at the bottom and work uphill. My guess is that they occcur there because of the natural back up at the curve, the turbulence, and it being at the bottom where all and any yeast, mildew, tap-hole shavings, etc must pass through. Another thing... In my experience, I almost never see from the outside where a blockage has occurred, meaning a connector or T may look perfectly fine from the outside - even be brand new - but have a plug of bark or whatever else inside. And one other thing... when you pull the spout and check the flow, sap may want to run right down the lateral and not up through the drop line. If it doesn't come up through the drop, just pinch the lateral downstream of the drop to force the flow to the drop. Again, if there is impeded flow through the drop, either that T or one uphill is plugged.

All that said, with so few trees on a line, and unless you know their flow very well from bucket days, it's VERY possible your trees are just running differently on different lines, even though it seems to you that all else is equal. Especially true in the early season as trees seem to "wake up" at different times.

Good luck. It seems like a pain but when you figure it out the satisfaction will be great! Like finding something you've lost.

[tgormley358]

Thanks Drewlamb. that's helpful, knowing where to start looking and logical as to the up or downstream likely clog.

Now, i have sort of a newbie mea culpa to report. I'm engaging all your brains in pursuit of my little mystery but in the end I find an embarassingly simple answer, as in the toast isn't toasting because "i forgot to plug in the dam toaster". So i walked my two lines tonite in the dark with flashlight and headlamp, studying every inch. First i found the usual big sap bubbles slowly making their down the line, slowly like a foot every 20 seconds. Then i looked further up the line and found tiny bubbles, more like condensation on a whole 30' section between two trees. I studied that some more, then started walking down the hill again when i noticed I'd left one of two tees on a big tree untapped. Kind of a big vaccuum leak, you could say.

I added a spout and connected to the tee, wondering what i'd see next. The big bubbles stopped in their tracks. Nothing happening. Now, the trees didn't run all that well today and the new tap i added didn't run any sap at all, so i'm not real worried. It's 42F outside now but it didn't freeze last night. My question is, when you've got a leak, a big one like this one, even a self-inflicted one, and you plug it, should one expect it to resolve fairly quickly on its own? Or do i need to do something to blow the air out? I wouldn't imagine so, but thought i'd ask.

I walked the rest of the line to see if i'd made any other newbie mistakes...looked OK to me. It's amazing i have any sap flowing at all. Good thing i have a day job. Next step if it doesn't run better is follow Drewlamb's guide. Thanks again!

[drewlamb]

Ha ha. Hey, we've all been guilty of just the same kind of thing at one point or another. No need to do anything with your lines to reestablish vacuum. It will develop on it's own once the sap flows again.

[rhwells2003]

Mind you this is my first year playing with 3/16. I set up 83 taps on 4-600' runs. I have been using 5/16 with vacuum for 4 years now so kind of know what to look for, for leaks. 2 of my 4 lines were struggling with vacuum. One would have about 3", the other would stay at 10" even though I have about 40' of drop. The top of my lines looked like nothing was moving. Then while working my way down the line I found a tap on both lines where a lot of air bubbles were coming out. I was thinking maybe a bad tee, stubbie, etc. I made a little contraption I've used looking for leaks in my 5/16 system. Its a small 1.5" vac guage attached to a small piece of 5/16" attached to an adapter spout. This way I can pull my stubby out, place this in and it'll tell me the vacuum at that tap. So I put this on these two taps that were sucking air to determine if it was the tree, or the tubing. Both places within 20min I was up to 25" of vac. Determined both trees are hollow, or have bad wood and it was venting my 3/16. I pulled both taps this morning, I'll see what my vac is tonight when I get home.

[tgormley358]

Glad to hear others have had it are having some of the same and that the vac will come back on it’s own. I can tell There’s a lot more to learn about tubing. I lack some of the science engineering background some of you may have but I make up for it hopefully with curiosity and scientific method. Sounds like I should try to find a pressure gauge for my lines. Praying for cooler weather here - you all up I’m NH and VT enjoy these next two weeks should be awesome.

[tgormley358]

Had a thought yesterday related to clearing clogs / plugs in the lines, so i thought i'd add it here. Is there such a thing as clear plastic tees? Since that's apparently where alot of plugs occur according to recent posts on this, it might make finding clogs alot easier. I read others here saying it's guesswork, just pull one spout at a time, and you rarely see the plug in a tee but that's where you find it. That's a helpful approach, but why not make it even easier, especially since clear plastic spouts are now pretty common. The tees i used are all black or solid green. A good portion of a few of my lines seem to be running slow -- sap sitting in drop lines not moving, so i need to get going on pulling things apart.

[Cedar Eater]

Most likely leaks or plugs at fittings. Tapping order shouldn't matter, unless you stopped partway through tapping to drill a hole in some metal or a rock with your tapping bit.

I've heard of tapping rock maples, but never metal maples. It's amazing what you learn on this site. http://mapletrader.com/community/images/smilies/lol.gif

[VTnewguy]

Had a thought yesterday related to clearing clogs / plugs in the lines, so i thought i'd add it here. Is there such a thing as clear plastic tees? Since that's apparently where alot of plugs occur according to recent posts on this, it might make finding clogs alot easier. I read others here saying it's guesswork, just pull one spout at a time, and you rarely see the plug in a tee but that's where you find it. That's a helpful approach, but why not make it even easier, especially since clear plastic spouts are now pretty common. The tees i used are all black or solid green. A good portion of a few of my lines seem to be running slow -- sap sitting in drop lines not moving, so i need to get going on pulling things apart.
This is a excellent idea! I would buy those!

[drewlamb]

This is a excellent idea! I would buy those!

Seriously. Me too. They do make polycarbonate spouts that are clear, but I've never seen a polycarbonate T.

[mol1jb]

Had a thought yesterday related to clearing clogs / plugs in the lines, so i thought i'd add it here. Is there such a thing as clear plastic tees? Since that's apparently where alot of plugs occur according to recent posts on this, it might make finding clogs alot easier. I read others here saying it's guesswork, just pull one spout at a time, and you rarely see the plug in a tee but that's where you find it. That's a helpful approach, but why not make it even easier, especially since clear plastic spouts are now pretty common. The tees i used are all black or solid green. A good portion of a few of my lines seem to be running slow -- sap sitting in drop lines not moving, so i need to get going on pulling things apart.

I wouldnt cut into a line just because the drops are moving slow. A lot of the drops on the lower part of my 3/16 runs move slow because they dont have as much vacuum as the higher drops at the begining of the runs. And sometimes my lines run slow because the temps are in the mid 30s and the trees just arent running as much compared to a 40 degree day.