Air-lock In 5/16th Tubing Lines?

[OakCorner]

Hi,

This is my first season tapping and the questions keep coming....! I ran a 500ft 3/4 mainline through the center of my maple stand and have 5/16th laterals coming off the sides. There are about 100 taps total on the mainline. Over the past few days the sap has started running, but when I look at the droplines and especially the laterals it seems that they are full, however I'm not getting much out of the mainline. I'm using CV taps and gravity with a pretty good slope. It seems like they are airlocked since when I remove the tap it all starts flowing again and the tree really weeps out of the taphole. Is this typical in that you only get a slow drip on gravity lines and it gives the appearance of the drops and laterals being "locked"? Should I open up the end of the mainline to release pressure and get everything flowing downhill? Thanks.

Edit: Out of curiosity, at one lateral end I poked a pinhole in the dropline just below the tap barbs and that released the sap in the entire lateral line. The tree also started dripping again. It's like there is back pressure in the lines holding the sap in the laterals and preventing it from easily flowing into the mainline. Are these CV taps really only meant for vacuum lines?

[unc23win]

That's normal for gravity you want it to look like its full and not moving. Do not vent it. It will drive you crazy looking at it but its actually running good when they appear to be full.

[Maplesapper]

You may want to read the article by UVM on Natural gravity.
The laterals are not to be vented but it wont matter if the mainline is.
Once the laterals empty into the mainline, the mainlines were designed to drop perpendicular to the slope

[PerryW]

That's normal for gravity you want it to look like its full and not moving. Do not vent it. It will drive you crazy looking at it but its actually running good when they appear to be full.

I agree with unc23win; By poking the hole, you relieved the natural vacuum and the sap flowed. this proves you have no obstructions in the lateral and everything is fine.

[OakCorner]

Excellent - thanks all. It was driving me crazy looking at the sap seemingly "stuck" in the laterals but I do understand the concept of a natural vacuum forming now.

[harrison6jd]

im in the same boat as you. yesterday i had 1 line flowing really well and one without even a drip, but sap in the lines. i checked every connection for blockage and was frustrated at the end of the day. just looked now and both are flowing equally. i worried for nothing.! lesson..stay positive!

[hounder]

Misery loves company! I just was coming on to post after looking at ours. Why are some of the trees leaking where it is looking like it is plugged? Is that just coincidence? I was going to take the day off and get those lines drained tomorrow - shopping for vacuum. We got about 300 gallons of sap today out of about 1400 taps.

[twitch]

Natural vacuum is a wonderful thing!!!!

[bstewar]

I'm on 130+ taps that are gravity and noticing the lines are all full. I know I just need to be patient and things will eventually happen.....(still frustrating though)

[harrison6jd]

very frustrating..............almost panic mode. with one line locked yesterday and one running fine. today was a different story. both running hard and picked up today by 3pm what i got all weekend. i feel much better.

[DrTimPerkins]

very frustrating..............almost panic mode. with one line locked yesterday and one running fine.

For those of you who feel you need to watch the lines constantly and fearfully my advice is ....RELAX a little. Watching lines like this only serves to make you anxious and perhaps make you do stupid things (like vent your lines). But then again.....it is entirely your choice to do those things if you like. But really....quit asking if there is a problem and whether it is OK to vent the lines....the answer is no, it isn't good to do that....and the answer won't change no matter how much you obcess about it.

Take a long pipe filled with sap that is NOT vented. Add a drop to the top, a drop will come out the bottom. That is the way UNVENTED tubing works. At the same time it does provide a little natural vacuum, and it also helps prevent the introduction of microbes into the taphole that result in premature taphole drying.

Take that same long pipe filled with sap and put a small hole (vent) in the top.....WOW...does that sap ever run fast.....but it only runs like that for a minute or two, then the pipe is empty. Then it stops. After that you get the same sap, drop goes in the top, drop comes out the bottom.

So your choices are, you can get your sap to run through the system really fast by venting, and get 1/3 to 1/2 LESS sap (due to faster taphole drying), OR you can leave the system unvented and get a lot more sap over the course of the season, but it doesn't appear to run nearly as fast.

Now for some of you, if you are use Ys to run two 5/16" lines together, you might be impeding sap flow in one line. Y'ed lines tend to have more problems, and you should avoid this practice.

[Too Tall]

Are "Y's" and "T's" considered the same? Could "T's" impede sap flow too?

[PerryW]

Are "Y's" and "T's" considered the same? Could "T's" impede sap flow too?

I think the point is that it's better to have a single lateral starting at the end tree and running though a series of trees and then into the mainline. Adding TEE's or Y's is like adding intersections to a roadway which will periodically stop traffic flow.

Having said that, there are instances where it would take a LOT more tubing to avoid TEE's or Y's, so just stick in a TEE and not worry about it.

[PerryW]

very frustrating..............almost panic mode. with one line locked yesterday and one running fine. today was a different story. both running hard and picked up today by 3pm what i got all weekend. i feel much better.

Lots of drama happening in the woods every time lines start thawing out and begin running. It's best to sleep late and check the lines when they are all thawed out.

[harrison6jd]

the lines were just installed 2 days before so i was just checking for leaks, blockage, and tightness in the lines as soon as things were a little warm. now they everything is all set, i go down at night to collect the tank. no more drama.

[windyacres]

Question for Doctor Tim Four - 3/16 lines wyed into 2 5/16 lines- all running side by side Observation one small line on each pair ran well, while its other half seemed almost to stall. I scratched my head for a bit and decided to put a short equalizer tee on- each side of the wyes - but crossed over to the one of the other pair . ( 2 equalizers making an X )basically equalizing all vacuum levels on both sides of wyes. Observation-- all 4 lines appeared to be running unimpeded. I will. send pictures to illustrate . Has anybody tried this ??

[maplestudent]

I'm anxious to see the pics of this configuration