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Old 09-24-2012, 10:03 PM
jbell36 jbell36 is online now
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Pressure and GPM - Designing System

i'll try to make this short...if you have a 5/8 meter with 50 psi on one side of town and a 5/8 meter with 90 psi on the other side of town are you able to put more heads on the 90 psi even though the meter is only 'rated' for what, 12-15 GPM?
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Old 09-24-2012, 11:37 PM
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cjohn2000 cjohn2000 is online now
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Pulling too much water through a meter can "knock" it out of calibration. Obviously higher friction loss through the meter and pipe to and from, which would result in a lower dynamic.
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Old 09-25-2012, 11:24 AM
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There are several flow-capacity standards for what you see as a 5/8 meter. The old standard was 20 gpm as maximum flow. Those meters are increasingly less common. A modern variation is a 5/8-3/4 meter, with the 30 gpm max flow rating for a 3/4 meter in the 5/8 package.
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Old 09-25-2012, 07:24 PM
muddywater muddywater is offline
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It would prob be safe to run 4 rotors per zone at 50 psi and 6 rotors at 90 psi. Using 2, 2.5, and 3 gpm nozzles depending on rotor radius. And if it hit the fan, you have room to nozzle down.
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Old 09-25-2012, 07:27 PM
muddywater muddywater is offline
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I have flow tested a 5/8s meter to push 30 gpm with 100psi. I could run 12 rotors at once(didnt put that many on a zone but it would push all of them)
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Old 09-25-2012, 08:02 PM
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1idejim 1idejim is online now
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Quote:
Originally Posted by muddywater View Post
I have flow tested a 5/8s meter to push 30 gpm with 100psi. I could run 12 rotors at once(didnt put that many on a zone but it would push all of them)
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I know you are using a good flow meter but how and where are you making your test connection?
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Old 09-25-2012, 08:21 PM
muddywater muddywater is offline
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Originally Posted by 1idejim View Post
I know you are using a good flow meter but how and where are you making your test connection?
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I tapped about 1' after the meter. Can't remember if I had the backflow on at that time or if it was before I put the backflow in. I posted a thread about a year ago, and Kirl said I should have had about 20' of pipe after the flow meter to get a more accurate number, but I think it was close. It would push 12 5004 rotors with average 2.5 gpm nozzles.

This was the first house in the neighborhood, so it was probably a lonely water main.
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Old 09-25-2012, 08:26 PM
muddywater muddywater is offline
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Well dug up those pics. Looks like it read 49gpm which sounds a little high. I know it probably had 60 psi dynamic pressure(visual guesstimate) with 12 heads running.



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Old 09-25-2012, 08:40 PM
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Mike Leary Mike Leary is online now
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Love those fuzzy, upside down/ sideways pics.
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Old 09-25-2012, 09:06 PM
txirrigation txirrigation is offline
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Or you can use the three variable equation. haha I kid I kid.

I have in fact passed this super secret equation on to another member though. They now hold the holy grail.
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