Basic question: tubing on flat ground?

[maple flats]

Back to maple rather than socks, The last 2 years I used about half CV taps and half Zap Bac taps. In year 1 I saw no difference (but I did not get any scientific data). In year 2 I changed the CV taps and levf the ZB taps, I think I had a very slight loss of flow in the 2nd year ZB taps, but again, no scientific data. This year I'm again using ZB taps for their 3rd and final season, and all new taps will be CV taps for this season and the near future.
About 3/16 vs 5/16, if you can't get at least 10-12' of slope, I suggest you use 5/16 if on gravity. However I use vacuum at 26-27" vac and about 40% of my taps are actually pulling from lower ground than the mainlines.
On my first big test of 3/16 on flat or lower ground I strung the tubing and then started to tap. I had 24 or 25 taps on each of my first 2 lines. Those lines went from tree to tree, until the reached the driveway into the sugar house. There I used an angle hook connector, designed for the end tree, but I installed it so what would normally be to the tap, I ran 3/16 up the tree to a height of 15', there it crossed the driveway (about 25' wide) to another tree, wrapped once around that tree and then down at about a 50 degree slope to a mainline which had the 26-27" vacuum on it. As I tapped the sap was running, I tapped the 24 or 25 taps, on line one, starting from the end tree, while my partner tapped the other line. When I got to the main line I was surprised that the sap was flowing not only thru from the far tap, about 3-400' of 3/16 tubing, then up to the 15' elevation across the diveway and down to the mainline. I had hooked the last hook connector to the mainline, but had not yet attached it to the mainline with a saddle. As I drilled the hole and worked on attaching it, my hands got very wet from the sap flow. That happened on both of those lines. That experiment I considered a success. For the cost of about 400' of 3/16 (plus some 5/16 for drops, tees and taps then 1 saddle, I was getting good sap flow from that challenging low area. The second line was the same. That was 3-4 seasons ago. I know I'm losing potential because of line friction, but the cost to do those the conventional way would have been far more costly. The next year I added 3-4 more lines, all on 3/16, again from areas lower than the mainline. Last year I added even more, again, from lower areas.
Personally, I willingly give up some potential/tap to get far more taps with the least cost to add them. This year I will have between 400 and 450 taps total at my sugar house and all but about 125 are be on 3/16 lines pulling from lower areas. Even with the loss, I got .52 gal/tap in syrup in 2018, and .49 gal/tap in 2019.
Yes, with a good vacuum pump (mine is a very old BB4 piston pump) you can pull sap thru 3/16 laterals. I keep my tap count to about 25 max for the 3/16 lines, I use 5/16 taps and drops then join it to the lateral using a 3/16 x 3/16 x 5/16 Tee. Could I get more sap, yes, but it would require a much bigger investment. My 3/16 lines are all lower at the far end away from the mainline, thus I'd need to run a mainline the distance, then I'd need to run 5/16 lines and saddles to the mainline with about 5 taps/line, not over 10, thus far more saddles, and a sap ladder or 2 on each mainline. I consider the lower investment in materials cost a far better choice. Maybe I could get .6 gal/tap going the traditional way, but would I recoup the cost in extra syrup before I retire (I'm now 73)?

[Sugar Bear]

It is important to recognize with Zap Bac and CV spouts that it is potentially possible that ...

1 The CV spout may perform better under a vacuum tubing system then the Zap Bac spout.

AND

2) The Zap Bac spout may perform better then the CV spout under a Drop Line to bucket system.

AND

3) Any combination or permutation of the above may be possible.

[30AcreWoods]

Dave, I would love to hear how this year goes for you in the final year of your comparison between CV/Zap Bac. I like the CV's, but perhaps that is only because I have over 50' of elevation drop from top-bottom on my 3/16" lines. I know it's simple physics, but to see friends and family look at the dial and see over 27in without a pump doesn't get old! I've also heard other sugar makers in my area say they can pull gravity lines over driveways with 3/16" tubing, and as long as there is enough drop in the system, it will pull up and over without any issue. I've begun to "trust" the system a bit more, and am beginning to grab lower area trees and add them to my gravity lines, and it does pull the sap. I see it as a bit of a challenge to work with the land, and see how much I can accomplish without electricity. I do have an entire sugar bush that heads downhill, directly away from my sugar house that I haven't yet tapped. I'm wondering if I should use 3/16" on gravity for that, and just use a gas water pump to bring the sap from a collection barrel "on the other side" back to the sugar house vs. setting up vacuum pumps to bring all of the tap lines "up, over and down". Any thoughts?

[kboone1]

I do have an entire sugar bush that heads downhill, directly away from my sugar house that I haven't yet tapped. I'm wondering if I should use 3/16" on gravity for that, and just use a gas water pump to bring the sap from a collection barrel "on the other side" back to the sugar house vs. setting up vacuum pumps to bring all of the tap lines "up, over and down". Any thoughts??

Just my experience, and I thought it was worth sharing (you can be the judge ha-ha!)

I am dabbling with a 4048 12V Shurflo system this year, teamed with a $50 Inkbird temp controller and $50 110AC-12V converter at my shack. I hate collecting, it takes the fun out of it for me since I am limited on time, and I have about 100 taps that are below my gravity mainline on the hill and also on flat ground around my shack. I have 140 3/16 gravity taps on my mainline, but wanted to get the rest of the potential without the collection effort.

I was reading a lot about the hybrid systems, asked some questions on here, and figured what the heck, I bet it works pulling stuff uphill and on flat ground, however no one really gave me any specific confirmation. Let me tell ya, I don't regret it one bit! I am pulling things a long way (1,500 LF on one hybrid line), through road culverts, from flat land, and also a couple hybrid lines that have gravity to start but then go low and back up to the shack.

I will say I spent a good bit of time making sure my system was leak-free at the manifold. The smallest leaks made the difference, and I even had to replace the Shurflo screen that came with the pump with a different one I ordered separate. I went from 18" to 26" at the manifold in a hot second, pretty crazy.

That being said, I have not tried anything like what you are talking about with a Shurflo. I am watching my lines race uphill through a road culvert I cross that is about 10 vertical feet in about 50 feet (so say 20% grade on teh 1,500 LF line) and I bet if you have a really strong downhill run on gravity, then bring it uphill, the gravity will enhance the ability of the pump since it isn't really working on the tap length of the run, just the excess coming back up. If I had your woods, after trying my stuff, I would give it a try and see what happens. I was so surprised by the system this year, I am already looking for ways to gain taps I never thought was worthwhile due to topography.

Again, just my thoughts, but I think it would be possible even just with a Shurflo if the hill wasn't crazy steep and super long, but I could be wrong.

Oh, I am running about 25" of vac on every tap with a $250 system, that's hard to beat from a value perspective IMO!

Kody