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The last 6 posts

Wednesday, August 13th 2003, 8:20am

by Rays Sprinklers

The design is correct with the nozzles. You always have to build with the worst circumstances in mind.....25 psi is extremely low for a rotor sprinkler system, but if you plan for 25psi, and your pressure goes up, then nothing more than good results can come from that, but if you build for 35 psi and it drops to 25 then you will get very poor results. I would use Schedule 40 PVC pipe from the mainline to the valves, and poly pipe (all 1") to the sprinkkler heads.

Thanks
Ray
Rays Above and Beyond Automatic Lawn Sprinklers

Monday, August 11th 2003, 6:03pm

by drpete3

.9 for 1/4 1.8 for 1/2 etc... yes you are correct. Second 25 psi is a little low. If your pressure falls to 25 psi after you get you rsystem installed then you need to fix this using a little smaller nozzles on your rotors. As I said earlier if you split that 90x90 and 16 heads into 2 zones with 15 gpm output @ 50 psi at the source you should be fine. ON each zone you will have 2- 1/4, 4- 1/2, and 2 full circle. Now this current situation puts you over 15 gpm usingf the nozzles that you made your prevoius calculations with but that is easily solved by going down one size on each and now you are well within your limits.

Let me tell you this also. My system at my house puts out 40 psi @ 12gpm and I have 2 zones in my front yard with 7 heads per zone and no problems.

PVC? I only use pvc on a main line and poly on the rest. I dont know the answer to that question.


Thanks,

Pete

Monday, August 11th 2003, 11:44am

by BTanner

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

Wednesday, August 6th 2003, 4:14pm

by Rays Sprinklers

Pete is right!

Thanks
Ray
Rays Above and Beyond Automatic Lawn Sprinklers

Wednesday, August 6th 2003, 12:53pm

by drpete3

If you are doing 16 heads I would break that into 2 zones and do 8 heads per zone and you will be fine. This will allow you to adjust up or down using different nozzles on your rotors. Also the 30' spacing is good to get head to head coverage.

Thanks,

Pete

Wednesday, August 6th 2003, 12:10pm

by BTanner

Residential well pump system (Question)

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 )