SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

Let me start by complimenting this forum and all who respond to the questions on such a wonderful site to gather info. I have recently built a house in the county and of course have a well pump. My well is 167 ft. deep and yields 30gpm, I have a 3/4 hp 18 gpm installed at approx. 100 ft. with 1" ploy pipe. The installer which knew I was planning to install an irrigation sys. says that according to the pump curve, the pump will pump approx. 23-25 gpm at the hieght installed and I should have no problem in designing a sys. as long as I limit the zones to 13gpm max. I had no idea of the engineering involved in this process and respect anyone who is a professional. I have been reading Jess Stryker's tutorial and find it very informative. I have performed the wet method of determining my design psi and flow to letter of the tutorial. I come up with following 15gpm @ 50 psi, my back flow psi loss will be 3psi and my mainline of 1.5 sch 40 pvc 150' is very little about 2psi maybe, rainbird 1" valve 3.5 at 15gpm, and I'm figuring 7 psi for laterals, so about 15.5 psi loss. My largest zone is 90'x90' and I plan to use rotors approx. 16 spaced 30 feet apart. Do I need to design my sys. by the manufactor specs on the rotors @ 35psi or 25psi. I appreciate any help. ( I'm getting confused )

Thanks for the replies, but I'm still confused. Please be patient, I will have my system installed one of these days. During my research over the weekend I discovered that when sizing flow rates of rotors always remember that the 1/4 is going to put four times the amount of water over that small area as the full circle nozzle in the same amount of time. (Once again, back to the graph paper and compass) So I'm guessing 0.9 gpm 1/4, 1.8 gpm 1/2, and 3.60 gpm for full circle. Would you agree? Also in my original question, I'm still not clear on the what psi to calculate my flows/distance with, 25psi or 35psi, based on my design psi & flow, the way I see it, I'll get one flow rate w/25 psi and another w/35psi and I don't want to flow more gpm than my design flow (my design flow is 15gpm @ 50psi). Just one more question, ("I know your getting tired of reading") on the lateral pipe material. Do you suggest sch 40 PVC or Class 200 PVC? Thanks again.



Edited by - BTanner on Aug 11 2003 6:14:26 PM

Edited by - BTanner on Aug 11 2003 6:17:03 PM