No more 3/16"- problematic

[blissville maples]

You have 300 feet of 3/16? Is this 1 line? If so it might be to much line. Also I've checked my lines and noticed 1 line with bubbles I know there is a leak . Another there is no bubbles and flows a full stream. No leaks

I was wondering this but if enough drop line length shouldn't matter right?? The air bubbles look to be gas out of the tree, not microleaks.......but yes if there are bubble then must be gas from tree or air from leak...

[blissville maples]

Has this particular pump ever been on a system getting more than 18"?

This pump has never been used anywhere else, first time hooked up it was at 27.5, found some leaks now at 28.5

[wnybassman]

This pump has never been used anywhere else, first time hooked up it was at 27.5, found some leaks now at 28.5

I re-read it, I didn't pick up on the 3/16ths only being part of the entire system.

So, you were experiencing low 18 inches on an existing 5/16ths section, switched it to 3/16ths and experienced the same mediocre results. Started switching it back to 5/16ths and now experiencing better results? That leads me to ask why the original 5/16ths was not producing those better results in the first place?

In all reality, I am not sure why 3/16ths is being introduced into mechanical vac systems. Wasn't it developed for its great natural vac properties with the right slope conditions? And wouldn't mechanical vac negate any natural vac that might be created with slope? I realize when there is no sap flow, there is no vac with natural flow, and with a pump there is all the time. For someone like me that has no interest in adding a mechanical vac system, it is great getting 27+ inches during the runs.

[wurmdert]

I believe Mechanical vacuum is suppose to add to existing vacuum already in a 3/16th natural vacuum setup untill you reach maximum achievable vacuum based on elevation usually 27 to 30. There will almost always be some air bubbles in 3/16 lines from tree gas. Very rarely will they be a steady stream of sap. Deadwood and hollow trees Im betting is a culprit. Ive noticed these before when I used clear spouts. I could see almost like foam pulling from the tap into the line.

[DrTimPerkins]

...I am not sure why 3/16ths is being introduced into mechanical vac systems. Wasn't it developed for its great natural vac properties with the right slope conditions? And wouldn't mechanical vac negate any natural vac that might be created with slope?

The effect is additive (positive direction, not negative). Pumped vacuum + natural vacuum = total system vacuum.

Generally such hybrid systems are used in combination with low-moderate vacuum pumps (sap pullers, etc.). Pumped vacuum can aid in leak detection in 3/16" systems, and help to achieve high vacuum in trees that aren't as high up on the slope. Even in a high pumped vacuum setting, 3/16" tubing can add a little boost in production if you aren't quite at max vacuum levels with the pump alone and the 3/16" tubing is set up properly. The reason it isn't used more by producers with high vacuum pumps is that 3/16" clogs up a bit easier and is also more subject to sanitation-related drop off in yield due to higher backflow episodes.

Dr. Abby and I have an article coming out in an upcoming Maple News https://www.themaplenews.com/ that compares the hypothetical relationships between elevation, vacuum, and yield in gravity, natural (3/16") vacuum, hybrid, and pumped vacuum systems.

[wnybassman]

The effect is additive (positive direction, not negative). Pumped vacuum + natural vacuum = total system vacuum.

Generally such hybrid systems are used in combination with low-moderate vacuum pumps (sap pullers, etc.). Pumped vacuum can aid in leak detection in 3/16" systems, and help to achieve high vacuum in trees that aren't as high up on the slope. Even in a high pumped vacuum setting, 3/16" tubing can add a little boost in production if you aren't quite at max vacuum levels with the pump alone and the 3/16" tubing is set up properly. The reason it isn't used more by producers with high vacuum pumps is that 3/16" clogs up a bit easier and is also more subject to sanitation-related drop off in yield due to higher backflow episodes.

Dr. Abby and I have an article coming out in an upcoming Maple News https://www.themaplenews.com/ that compares the hypothetical relationships between elevation, vacuum, and yield in gravity, natural (3/16") vacuum, hybrid, and pumped vacuum systems.

Thanks for the explanation! That makes sense.

[blissville maples]

I re-read it, I didn't pick up on the 3/16ths only being part of the entire system.

So, you were experiencing low 18 inches on an existing 5/16ths section, switched it to 3/16ths and experienced the same mediocre results. Started switching it back to 5/16ths and now experiencing better results? That leads me to ask why the original 5/16ths was not producing those better results in the first place?

In all reality, I am not sure why 3/16ths is being introduced into mechanical vac systems. Wasn't it developed for its great natural vac properties with the right slope conditions? And wouldn't mechanical vac negate any natural vac that might be created with slope? I realize when there is no sap flow, there is no vac with natural flow, and with a pump there is all the time. For someone like me that has no interest in adding a mechanical vac system, it is great getting 27+ inches during the runs.

Originally two years ago I had a dairy pump of only 18 inches, my other s.b has high vac and I saw the difference so I wanted to get high vac on my trees with good slope here so some would be at 18 and some at 20+......now I have switch to an airtech, initially I was going to leave the 3/16 because I figured it would be high vac everywhere, but upon testing I am wrong, the 5/16 has high vac and only 20% of my 3/16 lines are even close to high vac. It's a pain to switch it all but it HAS to be done.....I'm just applying the in field variables to table top research and theres a flawless in it for me here..... however not all my runs of 3/16 have failed only most and I think old hollow trees are the culprit, I've retapped some but certainly not going to retap all of them to try to eliminate the air bubbles and small leaks.....

[gfm]

Wurmdert My mainlines are new this year so they are very tight no sags. I was having issues when I first put in the pump with sap backing up in mainline then it would pull and dump and then back up again. I took off pre screen filter and installed recirculation line and now it is a steady flow.

[wurmdert]

Wurmdert My mainlines are new this year so they are very tight no sags. I was having issues when I first put in the pump with sap backing up in mainline then it would pull and dump and then back up again. I took off pre screen filter and installed recirculation line and now it is a steady flow.

I was curious as I have wireless 1/2 inch in place as gravity mainlines. Im sure even the slightest sag with 1/2 in fills the tube. I would like to try a sap puller next season, but hate to replace my mains.