What to do with sap in 3/16 line that will not run?

[PoseyCoMark]

So I have three different runs on 3/16 with 5/16 drops. Line 1 has 15 taps with 17' drop, line 2 has 18' drop with 17 taps and line 3 has 15' drop with 16 taps. Both line 1 and 2 are producing very well with good vacuum but line 2 hasn't put out at all with vacuum on 0. There is sap in the line up top, first 6 trees, but sap bubbles become very sparse after that with no movement. Checked lines from that point forward and they seem clear. I can't figure this out. Does this sound familiar to anyone? Thanks.

[BAP]

Check for a plugged tee.

[maple flats]

You might be plugged and not see it. As long as that lateral is not frozen, cut the line about half way down the slope to see if that flows. Then if it does, put in a new fitting and move down half the remaining slope and repeat. Also, do you have a way to put a little pressure on the bottom half before you join where you cut it? If yes, try pushing upward from the bottom, but not too hard, you don't want to push sap back into the tap hole.

[BSD]

if you've got a solid tube of sap there is a plug somewhere. had it happen on one line last year, it didn't surface as a problem for nearly 2 weeks after i started too. once you walk the line and find out where the bubbles and sap stop and the solid tube begins you'll find your problem. I use a rubber faced pair of locking pliers to clip off the line doesn't dump all over me when i'm opening it up with the tubing tool.

[PoseyCoMark]

I'm going to give that a try Maple Flats. BAP, I did disconnect from a tee about halfway and the sap began to flow. I ran out of daylight so put a container at the point and capped the other side. Tomorrow I'll have more time to check the rest of the line. Thank you much guys.

[PoseyCoMark]

BSD, what was it that plugged the line?

[BSD]

BSD, what was it that plugged the line?shaving from a tap hole and a partially collapsed tube at a fitting (combo problem for extra points)