help in troubleshooting 3/16 line for next season

[GV2]

I had a 3/16 line this year with 21 taps. The sap in the line at the top 7 taps was suspended. I replace the tee where bubble flow started downward, but that did not get the upward sap moving. A few days later for the heck of it, I pulled the next tap up for a few seconds and everything began to run, even after I put that tap back in. a few days later, sap was suspended above the same location. It was nearing the end so I just let it be.

Does anybody know what may be the issue? Two possibilities I came up with is perhaps poor slope in this section of the line (though the sap did run down when vacuum was interrupted), or too many taps (overloaded). My plan would be to put fewer taps with more slope, but additional thoughts about what was possibly going on is appreciated.

[danielschauder]

Natural vacuum or mechanical? What kind of flow days were you experiencing when sap was suspended? Did you have any vacuum gauges setup on the top of the line?

[abbott]

my gut feeling would be that they were just done running for the year. But I agree that a vacuum gauge at the top would be the best way to troubleshoot. If the line is overloaded I believe it is typically the lower taps that will not run.

[GV2]

Natural vacuum or mechanical? What kind of flow days were you experiencing when sap was suspended? Did you have any vacuum gauges setup on the top of the line?

Natural vacuum. The flow days were good. Good sap movement on the lower 14 or so taps was clearly visible. No vacuum gage this year but probably next year. Just odd that everything was flowing nice below this tee and sap was suspended above. I could see the stationary bubbles just sitting there. Again the tee was not blocked because the sap flowed throw it when I pull the tap above for a few seconds.

"Just done running for the year" is an interesting thought. The 7 taps above the flow were reds and the tap where sap began moving was at the top of a string of 6 or so rock maples, then reds again in the lowest section.

[Super Sapper]

It could be plugged on the top side of the tee where you pulled the tap. If you pulled the top tap and all the sap cleared it would show that the line was not blocked and it was just the red maples.

[rhwells2003]

Take this for what its worth b/c I don't use 3/16" but just a thought. You had good slope (20'+) between the flat top and the bottom right? And you say you had good flow coming at of the line? You say the lower 14 had good movement? Why do you say that? b/c you had a full volume of sap and could see the bubbles moving? But you had a full volume on the upper flat part but believe it was suspended b/c the bubbles weren't moving? Only reason I ask is b/c bubbles don't show if the sap is moving just shows the natural gases released by the trees in the line.

I think if you had a full line, with good slope, no leaks (or else you wouldn't have a full line), and you had sap coming out of the end that you had a good siphon and the upper sap was moving you just can't see it. Like others have said put a vac guage at the last tree next year to show you that you do have vac and if you have vac the sap IS moving even if it doesn't appear that it is.

[sugarsand]

It sounds to me that the trees were done. We experienced the same thing in places were there are softies, when they're done they're done. Clean your lines then watch next year to see how they perform.

[GV2]

Yep, 25 feet of drop, bottom tee to barrel. Sap running in the barrel on good days. Somewhat decent slope on the zigzag tubing with taps.

So the upper tubing that looked "suspended" had suspended bubbles for sure but possibly with no sap or suspended sap. I think I get it. With the upper trees done, that whole section of line was just one long vacuum perhaps. I did run hot water after the last run was done and got a great loud popping sound when I pulled the very top tap (first), which I am guessing was an indication of good vacuum. The water flowed through all the tees. Definitely got some good info from you all and much appreciated. I am going with upper reds drying up first. I think I will stick with the same line setup next year.

[RileySugarbush]

Also don't forget that the flow at the bottom of a line always looks more impressive since it is the sum of flow from all the trees. Up near the top, it is only moving at a drop or two per second if running much at all and can look like no flow, particularly if you have no leaks or gas from the tree.

[pipeline]

the tap where sap was suspended I would bet tap was not air tight. leak breaks your vac