When we talk about tubing systems, we have two roads to travel. One is a gravity system and the other is a vacuum system. A conventional 5/16” gravity system is not much different from running sap into a bucket. The yield is much the same as collecting sap in a bucket. When we add vacuum to a tubing system, we increase the sap yield 5% for every inch of vacuum we generate in our system. For example, if we produce 15 inches of vacuum in a line, we should be able to almost double our sap yield. The first year after installation is always the best. As time on a system accumulates, wear-and-tear hampers performance.
View resource → https://u.osu.edu/ohiomaple/2020/09/17/optimizing-the-performance-of-my-vacuum-tubing-system-part-i/