3\16 gravity trouble

[O3C]

Has anybody had trouble with lines getting vaporlocked ? Was working on lines Saturday and all were running, had bubbles moving clear to the top but some of the lines were not registering any vacuum. Started looking for leaks, some squirrel chews but mostly little slits at the tees and connectors . Went back Monday to finish working on leaks and the lines that didn't have vacuum on Saturday were not running at all. The lines that had vacuum that day were still holding that vacuum and the bubbles were moving, I wouldn't say that they were running hard. Walked the four lines that weren't running and found and fixed leaks, wouldn't run, checked the outlet of the lines and they were open, When I did fix a leak and cut the line, I didn't have sap running out like I did on Saturday. 3 of the lines that are running and three of the non running lines are basically identical, Same north facing slope , average 25 taps, same distance last tap to bottom of the line, new drops last year, new cv taps this year. These are mostly reds, I tell everybody I have the wrong trees on the wrong side of the hill. Also I jumped the gun and tapped the end of January. They were starting to drip and then we got a hard freeze for the next 3 weeks. So when troubleshooting is it pointless to do this unless the sun is out and your getting a good run ? Also, Those leaks at the tees , are they from freezing or my tubing tool? Thanks for any help, Ron

[DrTimPerkins]

Maintaining good vacuum is a skill that comes with experience. Finding leaks is very difficult if the sap is not running. What you refer to as "vapor lock" is actually what is generating the vacuum. If sap is not running in your lines, either the sap is not running from the trees, or, more likely, you have plugs in your lines. How old is the 3/16" tubing installation and how have you maintained it (cleaning or replacing tees).

[buckeye gold]

I have 6 laterals of 3/16 and last week 5 were running and one wasn't, it drove me nuts as I could not find leaks or blockages. I decided to just let it ride and Saturday it started and has actually been one of my good laterals. So be patient, sometimes a certain section of woods just isn't ready. I did notice there was pockets of sap just sitting static that made me think it didn't have leaks, because it hadn't drained. Also, check those tees closely, they will get locked with crud and it will be hard to see. It will lock up a whole line.

[O3C]

I did drill a couple of new holes because of being tapped for 4 weeks, nothing ran out of them. The line is at the most 5 years old, the drops were replaced last year. End of season line cleaning has not happened. I did have some discolored sections of line that were replaced , but most of it looks clear. Partial plugs at tees's are the hardest to diagnose for me. Thanks, Ron

[DrTimPerkins]

Unlikely the tapholes are the problem. If nothing ran out of the new tapholes nothing will run out of the old tapholes. Either it is too cold or the run has finished and you have to wait for a recharge (freeze) and subsequent thaw.

If you've not cleaned or flushed the lines, there are probably plugs. Sap might run OK the first run, but then the biological material in the lines hydrate and swell, plugging any tees or unions in the lines. Hate to say it, but you'll likely be chasing them all season at this point. Yes...the plugs are very difficult to locate and remove.

[O3C]

Glad to hear its probably not from early tapping. In my defense, I had just picked up a new syrup pan from AA and it was calling my name. The one thing I really like about maple is that it usually takes place when it's too crappy to do anything else then when spring does come, it's over. We also have a dairy and beef herd with mainly spring calving so pulling taps and cleaning lines get moved down the priority list, will have to rethink that this spring. Thanks, Ron

[tapdrinker]

brand new lines-I had to remove the furthest tap to get the sap to move. I put it back in-movement would stop. I see a ton of air in my tube and taps were flowing then it was plugged. I sucked for 1 min to get the sap moving but it wouldn't. Untapping the last tree in the line is the only thing that worked. Why is this?

[wmick]

brand new lines-I had to remove the furthest tap to get the sap to move. I put it back in-movement would stop. I see a ton of air in my tube and taps were flowing then it was plugged. I sucked for 1 min to get the sap moving but it wouldn't. Untapping the last tree in the line is the only thing that worked. Why is this?

Is it possible that your trees are just not producing today? Regardless of how much grade you drop for gravity vacuum, , ... the pressure from the trees should move some sap down the line. (Unless there is actually a blockage somewhere or restriction from a climb to make or ??) Taking the last tap out, likely just introduced a spot where air could get in, allowing the sap to run away. (like picking up a column of water in a drinking straw, with your finger over the end..... and removing your finger) Being your sap ran away when you opened it up.. would indicate that you don't have a blockage... So maybe the trees just aren't pumping today??.

Describe your system a little more...

[tapdrinker]

The lines are gravity and drop about 8' over 100' into collection buckets. Taps are about 2-3' above the lines. 4 lines were moving just fine and one wasn't which made me think something is wrong with the line. I looked for wood in the lines-checked the taps to make sure they were running and 4 out of 5 were. It just wouldn't move through the line. If I sucked on the tube to drink the tap it worked. NO suction-no movement. Just weird. But yes like the straw affect! Really good way of describing the issue.

[wmick]

your collection buckets... are the ends of your lines submerged under sap? if so pull them up so the outlet is in free air. it takes a fair bit of pressure to push air bubbles down below liquid level... this could be restricting your flow.

[maple flats]

5 yr old, uncleaned lines are my thought. I got good flow on 3/16 BUT I change every tee and connector in the system every year, plus I flush the lines after every season. Then last year I filled the entire system with calcium hypochlorite and drained it mid fall. Even then every tee and connector was changed. The I.D. of the fittings on 3/16 is so small that it takes almost nothing to plug it.
In fact even 1 yr old lines would often plug if not cleaned and new fittings. By the way, you should change the fittings after 1 day sap flow, in case anything plugs.

[O3C]

Update, everything is running good. Found a few more leaks and a bad guage . The Lord has tried to teach me patience several times in my life ! Ron

[buckeye gold]

I have two laterals that were my fall taps and I left them in. They ran .6 gallons per tap last night and they were tapped December 16th 2020 ( 10 weeks ). So if you keep them clean, tight and no leaks they will preform.

[Swingpure]

5 yr old, uncleaned lines are my thought. I got good flow on 3/16 BUT I change every tee and connector in the system every year, plus I flush the lines after every season. Then last year I filled the entire system with calcium hypochlorite and drained it mid fall. Even then every tee and connector was changed. The I.D. of the fittings on 3/16 is so small that it takes almost nothing to plug it.
In fact even 1 yr old lines would often plug if not cleaned and new fittings. By the way, you should change the fittings after 1 day sap flow, in case anything plugs.

Just rereading old threads. What does the last sentence mean? (I highlighted the last sentence)

On a separate note, if sap is coming out the end of the tube reasonably well, do you need to walk the lines and check them? All of my lines have sections of terrain that are challenging to walk, enough now, I guess I was naive to think that they would be relatively maintenance free and that I would not have to walk in those areas too often. Man, this spring is going to be a learning experience.

[buckeye gold]

Just rereading old threads. What does the last sentence mean?

On a separate note, if sap is coming out the end of the tube reasonably well, do you need to walk the lines and check them? All of my lines have sections of terrain that are challenging to walk, enough now, I guess I was naive to think that they would be relatively maintenance free and that I would not have to walk in those areas too often. Man, this spring is going to be a learning experience.


There is no such thing as maintenance free. With 3/16th what you learn is to watch the flow at the bottom of your runs, close to your collection tank. You can pretty well read what is happening right there, with a little experience. You'll learn that when sap is running too fast you have a leak or chew. You will learn really slow or no flow means a plugged fitting. Watch for change and learn what is normal for your lines. It won't be too troublesome once you get it down.