The key to getting good flow using 5/16" runs is having a straight final run of tubing from your lowest tap to the collection barrel of 75 feet or more and a drop of 5 vertical feet per 25 feet of run.
You want no fittings of any kind mucking up a final run.
Less then this will still work but more then this will work better and support more taps and more fluvial taps.
So if it is a 75 foot final run then it should drop 15 vertical feet. These numbers have provided up to 17 inches of mercury for me with 7 taps.
More and/or longer pitch then that would get you more inches of mercury and support more taps on the run.
The pitch of your tubing run above the lowest tap is not as critical as your final run as described above.
But tubing in the "taps" area should be straight and pitched downward as well as possible. But pitch in this area is not required however it will prevent back flow into the tap holes at sap flow shut down time, if that sap is not drawn out at shut down time when the sap column in the "final run" collapses, as it will be in a entirely pitched run. Sap that collects in any Non pitch area will act as a counter weight against the column of sap in the final run, reducing its efficiency and effectiveness of suction at tap hole location.
The natural vacuum is generated by the sap column that collects and holds in the "final run" of tubing. It is the vacuum engine. It is the CRUX behind the formulation of natural vacuum.
This final run is critical in making your tubing runs more or at least as efficient as if the taps were each on individual drops to buckets. If you don't have or can not have these "final runs" set up properly you will be more efficient with drops to buckets.
3/16" tubing will more effectively set up these final run columns on less pitch but are laced with other pit falls.
If you want or can generate natural vacuum in the run and be as or more efficient as taps on drops to buckets, venting of any kind in your run is prohibited.
If your system is "swamped/sap locked" at tap hole locations and the run does not have enough slope to generate any effective level of output flow on the encased column of sap and thereby only creates enough vacuum to keep sap "stuck" in your lines , I suggest venting at the beginning/top of the run. This way you will run closer to the efficiently as taps on drops to buckets and really not expose tap holes to any more air then taps on drops to buckets would expose them to. So you may as well be vented in this scenario.
If the slope in your run is very small, your sap may back flow at the vent. If that happens take down the lines and put buckets up.
More then anything else taping maple trees is like poker. Got to know when to hold em and know when to fold em. And make the best of what you are dealt.
You can't make a Royal Flush out of a 2, 4, 7, 9 and jack of any kind.
Last edited by Sugar Bear; 09-19-2021 at 08:55 AM.
If you think it's easy to make good money in maple syrup .... then your obviously good at stealing somebody's Maple Syrup.
Favorite Tree: Sugar Maple
Most Hated Animal: Sap Sucker
Most Loved Animal: Devon Rex Cat
Favorite Kingpin: Bruce Bascom
40 Sugar Maple Taps ... 23 in CT and 17 in NY .... 29 on gravity tubing and 11 on 5G buckets ... 2019 Totals 508 gallons of sap, 7 boils, 11.4 gallons of syrup.
1 Girlfriend that gives away all my syrup to her friends.