Pond Boss Forums Thread Like Summary - 8" siphon: static pressure at output valve?

Great website - been reading for several months. Many excellent posts and answers.

I have a 10 acre lake with an 8" siphon as a primary. Current Watts lug style butterfly value leaks when charging the system enough to consider replacing. Found a PVC version for ~$250 as opposed to steel Nipco for $350 and Watts at $275. The PVC is rated for 150 psi. Can not find the specs on the current Watts valve, which was installed in 1988 (and does not have a rebuild kit). The drop is ~40' over an 80' discharge. Am I correct in assuming a 150 psi rated valve is adequate?

The "lattice" is the inlet strainer. It allows sediment and moderate size debris that can't get stuck in an elbow to be removed, and also prevents any one area having high suction that could cause a clog. I cut it on-site with an electric chainsaw in a way that allows water flow from the top and sides, without risk of the pipe sucking out the supporting sediment and digging a hole/breaking off under it's own weight (14#/ft). When not in siphon mode, anything stuck, can float out...Makes it as close to clog proof as is posible. The valve is on the air break, and the pipe with "holes" in the top cap allows air to enter the system to break the siphon, yet brings all parts inside the dam, and below the frost line so the system is freeze proof. An external air break that typically extends out and over the water is notorious for getting broken, either by something hitting it, or in cold climates, ice lifting and busting the pipe...That style air break also gets easily clooged by mat algae and leaf/stick litter, which causes the air break to fail and the sipho to over-drain the pond.....By moving everything inside the dam, and below the frost line for any climate, my design can be installed anywhere, and is virtually fail proof and maintenance free....the only visible indication of the entire system, is a landscaping access cover similar to those used for lawn irrigation controls. To my knowledge, I am the only person that has designed and installs a siphon system like this, so I don't want to show just how I accomplish everything below grade. The seals are rated for a 100 year longevty and allows for some flexibility, so it won't break from water hammer or soil shifting

[img]https://i.imgur.com/DRIGBqA.mp4[/img] Click link to view a "test" run