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New Member


Friday, June 1st 2007, 5:02pm

Best Valve Size

<font color="green">Per Rainbird's recommendation, I am going to use 3/4 polypipe for my system. Rainbird also recommended 3/4 inch valves for my system. However, I decided to use Hunter valves and rotors but Hunter only offers 1" valves and larger.

I guess I can use 1 inch valves with 3/4 polypipe. But I would like to know what is most appropriate. Perhaps 1 inch is better. Perhaps it's worse. I don't know but I'll buy whatever size is most suitable.

FYI, my meter is 5/8", my main copper house piping is 3/4", my house static water pressure is 60 psi, and my flow rate is 8 GPM.

Please recommend what valve size is best.
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Supreme Member

Posts: 5,305

Location: Metro NYC


Saturday, June 2nd 2007, 5:56am

Go ahead with one inch valves. That's what pros do.


Supreme Member


Saturday, June 2nd 2007, 7:23am

While you're at it..use 1" poly...not that much more money and more of a standard size.....
Sprinkler Solutions, Inc.
Arizona and Colorado


Supreme Member


Saturday, June 2nd 2007, 10:44am

another for for 1" all the way


New Member


Saturday, June 2nd 2007, 11:53am

Isn't the size of the poly dependent upon my house supply pressure and flow rate? I figured that's why Rainbird specified 3/4 inch. I would think that oversizing my poly based on my 60 psi, 8 gpm capacity could make the system less efficient. But I am not at all sure.

According to Hunter's Sprinkler System design handbook, the max flow rate for 3/4 inch poly is 8 gpm. For 1 inch poly the max flow rate is 13 gpm. However, since my house supply is only 8 gpm wouldn't the 3/4 inch poly be perfectly matched to my house supply (both being 8 gpm)?

Please advise.


Supreme Member


Monday, June 4th 2007, 3:39am

upsizing your pipe decreases the pressure loss, so your system will be more efficient.

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