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jmd4j

New Member

Posts: 8

Location: TN

1

Friday, January 13th 2017, 12:29pm

Dumb/Basic Pipe Reducing Question

I guess the easiest way to put it is look at my diagram. Is the A scenario that much better than B? I've designed my system on a couple of online sites, and the diagrams always show the 1" pipe from the manifold intersecting the 3/4" somewhere in the center of the zone, to be equidistant to the heads. I'm just trying to wrap my head around why can't I just reduce t form 1" to 3/4" and then install my heads on that line. Sorry for the basic question...my brain just seems to be freezing at the moment!

Wet_Boots

Supreme Member

Posts: 5,243

Location: Metro NYC

2

Friday, January 13th 2017, 12:46pm

the pros deal with this question by way of brute force - they stick with one-inch pipe throughout the zone

for the do-it-yourself crowd who are using standard rotor heads of about 3 gpm flow rate, go by the simple rule of having only two heads as a maximum being fed from a 3/4-inch pipe

kosterirrigation

Active Member

Posts: 28

Location: NC

3

Monday, January 16th 2017, 4:04pm

We really need to know how many sprinklers and what will they be putting out
for GPM each. And how far apart.

If this is a small residential yard, With 4 to 6 rotor heads per zone, You will
more than likely only use 1" for everything.

Whats your available water pressure.
Licensed Plumbing & Irrigation Contractor

jmd4j

New Member

Posts: 8

Location: TN

4

Wednesday, January 18th 2017, 7:38pm

Thanks for both of your help! It is just a small residential yard..about 5000sf. I'm getting right at 7 gpm at 40 psi...and thats after my pressure regulator. I haven't checked pressure before the pressure reducer...but seemed to be about 100psi before I installed the reducer if my memory serves me correct.
Attached are two pics...one showing the layout of the pipe that the web design tool laid out, and the other one shows the zones/sprinkler heads. I input the gpm per head next to each sprinkler head that was shown on the layout. The design also included one zone with only one large sprinkler that ran directly to the center of my yard, but I honestly don't think I need that one...but can add back in if need be. I'm also contemplating on having the two zones on the right side of the driveway...and wondering if I could get by with just one.


This post has been edited 1 times, last edit by "jmd4j" (Jan 19th 2017, 7:40am)


Wet_Boots

Supreme Member

Posts: 5,243

Location: Metro NYC

5

Thursday, January 19th 2017, 8:48am

If this is a home with a basement water meter, you might take the time to make your supply connection now, and establish new flow and pressure numbers to work with.

"about 100 psi" is a pressure enough for you to consider having a pressure reducing valve in the sprinkler supply, acting independently of the one feeding the house plumbing. You definitely want more than 40 psi static pressure for the sprinkler supply, and you also do not want the sprinklers to sap pressure from the reduced-pressure house plumbing when they're on.

jmd4j

New Member

Posts: 8

Location: TN

6

Thursday, January 19th 2017, 9:04am

My meter is next to the road...in about the bottom right corner of the picture. The previous owner installed the reducer just past the meter, but I have no issue in relocating the reducer closer to the house where it actually goes in, and adding another one onto the sprinkler supply.

This post has been edited 1 times, last edit by "jmd4j" (Jan 19th 2017, 9:11am)


Wet_Boots

Supreme Member

Posts: 5,243

Location: Metro NYC

7

Friday, January 20th 2017, 10:59am

Any roadside meter will allow you to draw much more water than from a connection at the house. Tee off for the sprinkler system right after the meter, and you can expect a minimum of 15 gpm to work with.

What's your location? There are considerations involving a backflow preventer that might have to be located above grade.

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