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So If I take 50 static and deduct the meter, mainline, PVB, valves, laterals, etc... I'm down about 15 to 35? Darn, that sucks. Can anyone explain how I have a 5/8 inch meter, 50 psi static, and I can get 25 gpm out of the PVB? Doesn't seem right. Having a hard time accepting that. Seems that with a 5/8 inch meter and 50 static I should be only getting maybe 12 gpm. I wonder if the pressure gauge is just wrong and the pressure is actually higher. Will the PGP work properly at 35 psi?
Yeah, it sucks. I didn't want to accept it when I did my tests either, but it's true. You're getting 25GPM but you probably only have 5-10 PSI as the water exits the PVB, if that. If you hooked up a pressure gauge right next to the outlet of the PVB @ 25GPM you'd see very low pressure. If you had a valve on the outlet of the PVB and gradually closed it to reduce the amount of flow the pressure on the gauge would start to rise.
Oh and for what it's worth I have a cheaper hose bib gauge like you. If I open my hose bib fast enough (it fully opens with 1/4 turn) it will spike to 82PSI and stay there. If I slowly open the valve it clocks in at 51PSI. The gauge is cheap so it just sits at the highest reading it sees until all of the pressure is relieved.
So I bought a water pressure gauge and attached it to the outlet on the PVB and got a static pressure of about 50-52 psi depending on when I measure it. From there I plan on using 1-1/4 inch piping throughout, 1" valves, and pgp heads and a max of 15 gpm for any zone. You might recall from another thread that my 5 gal bucket test gave 25 gpm but I will only use 15 gpm. So to calculate my working pressure do I deduct pressure loss only from everything that is downstream from where I measured the static pressure (the outlet on the PVB)? or Do I need to also include the pressure loss from the water meter, 50 ft. of mainline, and the PVB that are upstream of where I measured the static pressure?