Greetings, I learned a terrific amount from this forum (Peter, Kiril, Mike, Rotor, everyone else) and installed my own homeowner system last year. All is running well after 1 year, no problems, no dry spots and less water usage than neighbours! Anyhow I want to help out one of my neighbours. He has a larger lot. 40+yr galv 1" supply line, with 3/4" mainline and 60ft laterals with 8+ sprays on each, pushing 14gpm+. Used to work, now on some zones the heads don't even pop up fully. Probably the line rusting etc. I used 1.25" main/1" lateral for an even smaller configuration. So I plan to put in MP rotators to avoid too much digging. My design cuts the number of heads by over half, and the gpm on the zones by 2/3, and gets rid of some mid-lawn spray zones completely. My question for the pro's surrounds this valve (pic here). I'm sure you are all familiar with it: 1) What's the pressure loss in this thing - is it worth cutting out and replacing with an ASVF? It sounds like water is gurgling its merry way through when zones are running, but it doesn't feel like there's a lot shifting through it. 2) Also is it possible to open/close the valve manually without using the timer? It doesn't have a big friendly knob on top like the ones I installed Thank you all, N.