5% slope and 3/16ths.

[vach50]

Curious what results people have seen running 3/16" tubing on slope around 5%. I know vacuum level depends on total drop. Does the rule of 0.8" of vacuum per foot of drop still apply at 5% slope? Is 3/16" a positive or negative compared to 5/16" tubing at this slope? I'm switching over from buckets and will go with 3/16" if it is at least as good as buckets at this low slope. Thanks.

[maple flats]

From everything I know about 3/16, the % of slope makes no difference, just the total drop on the line. To get the best results you need the 30' drop after the last tap, but even without that much at the end you still get decent vacuum. With 3/16 you don't try to keep your laterals under 100'. What I did (which worked very well) was to string back and forth, picking up a lot of of taps (up to 35) near the top of my slope, then I ran downhill to my mainline. My early lines were all at or near 30' drop after the lowest tap, later installations I tapped as I went down the hill too, so my lower taps were much lower than the 30' above the main. On those first ones I put in separate laterals in 5/16 to pick up the lower taps. Watching the 3/16 flow was very interesting to watch. Even when I had a limb fall on a line, it did not seem to affect the line. The sap went down under the limb and climbed back up to the next tapped tree just as fast as it did without the tree limb. My laterals were from 250' to over 500' long on the 3/16. If you have 5% slope, ideal would be 600' of lateral after the last tap, but even half that will do fairly well too.
However, you need to realize that my system was a hybrid, I had the whole system on vacuum too.

[vach50]

I won't have any additional vacuum, just the natural vacuum. My local supplier says he had one person use 3/16" tubing with 5% slope and was not happy with the results, "could have hung buckets" was the comment. Curious if others have experience with the same conditions.

[motowbrowne]

I won't have any additional vacuum, just the natural vacuum. My local supplier says he had one person use 3/16" tubing with 5% slope and was not happy with the results, "could have hung buckets" was the comment. Curious if others have experience with the same conditions.

I don't have much slope. Not sure if it's 5%, but pretty close to that. I ran 20 taps on 3/16 and got close to 20" of vacuum at the top. I don't think I've got even 30' of drop over the length of my line.

These taps far and away out performed my buckets. It wasn't even close. Next year I'll be changing 75% of my buckets and all of my 5/16 gravity tubing to 3/16. Yeah, you could hang buckets instead of 3/16. I've got lots to sell, if you're in the market ;).

[vach50]

Great feedback, thank you! How many feet long were your runs? How many taps per run.

[motowbrowne]

Only one run with 20 taps. It was about 600' long.

As Dr. Tim has pointed out, a new 3/16 system has two huge advantages over buckets. One, it's got vacuum, and two it's brand new perfectly clean tubing. The first advantage will continue into following years (assuming it doesn't get plugged). The second one will require steps to maintain.

After I pulled my buckets and stopped collecting at the end of the season, I neglected to pull the 3/16 taps. When I went to take down the line, those 20 taps had run another 225 gallons.