Main Line Pitch

[David Lyman]

Are there any problems with a 1" mainline with high percentage pitches? I'm considering running mainlines up some pretty steep, upwards of 40%, side hill and then running short laterals with 5-8 taps. This will be going into 2" over 1&1/2" wet dry system. I have heard some discussion on problems with too much pitch.

[maple flats]

High pitch mains cause turbulence in the line. Get a copy of Steve Childs' (Cornell Maple Specialist) tubing notebook, it will cover the design possibilities for your situation.
In general you are best off making the main at 2% slope, gradually climbing the contour lines and make the lateral as steep as possible. If steep enough they can be much longer than 100' with no issue. In fact, if 40% slope you can go to about 25 taps/lat. and get good natural vacuum. Some doing this even run 400'+ with good results.

[David Lyman]

Any problems with running the wet dry lines up that slope and then running mainlines horizontally??

[BreezyHill]

The issue will be major turbulence where the high speed flow of the 1" meets the wet line. This will negatively affect vacuum transfer. The trick will be to attach so *** to provide a smooth fluid transition and maintain adequate vacuum transfer. Whips on low slope work well. On a rapid slope transition fluid will not maintain bottom location in the tubing. This will intensify turbulence on wet line transition. A manifold position between wet and dry line with a y or k entrance to the wet line will reduce turbulence by slowing the speed of the sap and allowing gravity to direct the flow. For that step of a slope I would suggest angling the mainlines connection point so that sap will flow around the manifold side to slow the flow and reduce turbulence in the manifold. This can be done by making a 3" or 4" PVC manifold and taping a 1" attachment point that is angled as desired.
Attaching the dry line to the top of the manifold will allow for maximum vacuum transfer and maintain fluid flow.

A glass manifold system and releaser demonstrates a lot, as it relates to fluid dynamics and flow transition principles, 1" into a 1.5" causes major turbulence and a slight vacuum reduction disturbance affects.

Ben