some laterals not draining-WHY?

[dano2840]

i have 2 dozen laterals that dont seem to be draining some of them have sap full right up to within 1" of the tap and ive got 30" drops that are for the most part straight up, they have PLENTY of slope on them more than the minimum 5% grade as recomended, and some have 6 taps on them and are 1"from the bottom of the taps and some have 15, they are larger maples and most with BIG tops that are producing lots of sap but they dont seem to be draining and they arent clogged with wood chips from the drill as i clean my tap holes with a stick and inspected some of the lines, even when i lift it up as high as i can go then it only starts to move VERY slowly, my main line isnt full because most of the full lines are near the top, the others mid to top, maybe some sort of vapor lock type thing although i cant figure how thats feasable, the freacken tank is getting pretty near full in the past few days so its not like i need the extra sap but i dont like it sitting in the lines any one know whats going on???

[RileySugarbush]

I'm not much of a tubing guy, but if you don't have any leaks and have small laterals and drops it makes sense that they do not drain. It's like putting your finger over the top of a straw and pulling it up out of a glass of water, the straw stays full.

[mark bolton]

My tubes were full of sap the other day and not draining much. On one of the lines I opened up the top and put in a vent and left it for 24 hours- it produced 1.5x as much sap as the non-vented line. I think it is a vapor lock and they need to be vented. Some people say to leave the lines closed but it doesn't work on my setup.

[PerryW]

There will always be sap in the laterals since it is a closed system.

If you try pulling one of the highest taps out of the tree, and you can feel a vacuum by placing your finger or tongue over the hole; then everything is working properly.

[Clan Delaney]

My whole yard is nothing but 5/16, and they're always filled with sap. I used to think the same thing, that nothing was draining, but go down and look at the end of the line on a warm day and the sap is coming out in a constant pencil lead thick stream. Think of it as priming the system. And like PerryW said that sap in the lines pulling downhill provides a small measure of natural vacuum, so you're getting more from those taps that if they were just buckets.

Patience, Grasshopper. :)

[Brian Ryther]

Pulling a tap might let the sap evacuate the line, but it is introducing air to your tap holes. Air = bacteria. Bacteria = tap hole colsure. Tap hole colsure = short season. Keep the spiles in the trees.

[Clan Delaney]

Pulling a tap might let the sap evacuate the line, but it is introducing air to your tap holes. Air = bacteria. Bacteria = tap hole colsure. Tap hole colsure = short season. Keep the spiles in the trees.

Plus, you'd be pulling them out constantly when they filled up again. They're fine. Your tubing is working hard so you don't have to!

[PerryW]

Pulling the tap out is just done temporarily to see if things are working properly.

As Patrick and Bryan said, temporarily removing taps may introduce bacteria into the taphole, so this procedure should be used sparingly. Sometimes I have pulled an upper tap and seen sap squirting out at high pressure which indicated a blockage or frozen line below. In these cases, diagnosing & fixing the problem is more important (i.m.o.) than the potential to shortened the season on one taphole.


You can also grasp the tubing at any point in the line and twist it so that the you create a small sag in the pipe. Watch carefully and you will see the sag filling up with sap.

[maple sapper]

I could be wrong on this, but what I experience is when sap is having a run, the pressure in the trees will litterally push it down the line. Its like having it hooked up to a expansion tank (the tree). My lines have sap in them at all times as well. maple sapper

[WESTVIRGINIAMAPLER]

I don't have problems with sap backing up in my lines even with 45 taps on a line unless I have sags in the lateral around a huge tree that is 4' in diameter and maybe difficult to keep proper slope but the sap never columns up the tubing higher than the sag.