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# Planning out sprinkler head spacing

## Planning out sprinkler head spacing

#1
09-04-12, 08:02 PM
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Join Date: Nov 2011
Location: USA
Posts: 27

I'm ripping my hair out trying to figure out head spacing. The heads I have (Hunter PGJ) throw 15' to 37' feet! That's a large gap. Where do I start in mapping out head locations?

#2
09-04-12, 09:13 PM
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Location: Galivants Ferry SC USA
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You need to know your total GPM. Also your dynamic pressure. Pick out the # of heads vs the distance you need from the chart on the hunter site. I linked below.

Example: Lets say you produce 10 gpm @ 40 psi. And you need to throw 25 ft. From the chart you can run 5 heads with a 2.0 nozzle installed. That would be one zone. Each head will produce 2 gpm x 5 for a total of 10gpm.

No say you have a larger area to water at 37ft. Look at the chart. You can run two heads with a 5.0 nozzle installed. That will be zone two. each head will produce 5 gpm x 2 for a total of 10 gpm.

Hope this makes sense. There are other factors involved such as pipe sizing and friction loss through the piping.

PGJ | Hunter Industries

#3
09-05-12, 06:50 AM
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Join Date: Nov 2011
Location: USA
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Thank you. How do I determine GPM and pressure?

#4
09-05-12, 07:25 AM
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There are many sites online that tell you how to determine your water pressure and gallons per minute. Here is a link if you are on city water and here is a link if you have a well.

#5
09-05-12, 08:01 AM
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Join Date: Nov 2011
Location: USA
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Some neighbors have told me that our sprinkler systems in the neighborhood have a different water supply than the hose bibbs on the outside of the house. Is this common? Would that mean I should check pressure and flow from the sprinkler system itself?

#6
09-05-12, 08:13 AM
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Best is to check where you will be tying into your water supply. It all depends on how you will install your system. You can connect at your hose bib, a water line inside your house, the main water line leading to your house, a totally separate connection to the municipal supply, to your houses well or to a dedicated irrigation well.

#7
09-05-12, 04:25 PM
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Join Date: Nov 2011
Location: USA
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Sorry guys, I'm an idiot when it comes to this stuff. I already have a sprinkler system installed that needs to be redone. It was installed by someone who literally knew nothing about installing sprinkler systems. The system never worked after install, so they let the yard go and eventually foreclosed on the house.

So there is a valve box already installed in the backyard. I just need to add one or two valves and lay down new pipe and heads. I confirmed with my neighbor that the water fed to our sprinkler systems is completely different water than comes to our house. So where do I test the water pressure and water flow?

Here is a picture of something on the outside of my house:

Attached Images
#8
09-05-12, 04:37 PM
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First I would say try to identify the water source. Well? Does the pump work? Stuff like that. Do you have water from there know?

If from a well the pump should have a gauge. Then you will need to do a bucket test to determine your GPM.

#9
09-05-12, 05:48 PM
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I live in a newer neighborhood, built in 2006. No wells, just city water. The sprinkler system in the front yard was put in by the builder and works great. I just need to do the backyard.

#10
09-05-12, 05:53 PM
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It was installed by someone who literally knew nothing about installing sprinkler systems. The system never worked after install, so they let the yard go and eventually foreclosed on the house.
So the front yard works great by the builder and the back yard stinks because it was installed by someone else?

This will be easy then.

Let us know and we can guide you further.

#11
09-05-12, 06:31 PM
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Join Date: Nov 2011
Location: USA
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Yes. Please help! The zone lines are already, I just don't know where to place the heads because I don't know pressure and flow. I plan on using funny pipe off the zone lines for the heads.

#12
09-05-12, 06:42 PM
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OK.

1. The front yard is fine, correct? How many zones?
2. The back yard just has the valve box in the ground and nothing else?

Explain what is there better.

While you are at it, the heads in the front are PGJ?
Plus what area do you need to water in the back? Try to draw a diagram.

Last, see how many heads run on each zone in the front. Then for each zone check every nozzle and tell us the nozzle # for each head in that zone. This will help us determine your GPM.

Some work involved but that's the info we need.

#13
09-05-12, 07:34 PM
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Join Date: Nov 2011
Location: USA
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Front yard is fine. 2 zones. One zone is 4 rotors and the other zone does the 2 strips and the heads are not rotors. Picture of front yard and back yard below. Rotors in the front yard are Rain Bird 5000s. Heads in the backyard will be Hunter PGJs. Back yard is pretty big and needs to be redesigned. Home was a foreclosure and yard is gone. New edging is needed as well. Figured the sprinkler system was the first step.

I don't mind buying the equipment necessary to test pressure and flow. Just don't know where to test it at.

#14
09-05-12, 07:41 PM
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Join Date: Nov 2011
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The backyard has a valve box with 3 valves. (We'll need to add 1 or 2 more.) There is a sprinkler system installed in the back that is so horrible, we'll just bury it. New zone pipe has been laid in the backyard (1" sprinkler pipe) and we'll run funny pipe from it to wherever the heads need to go. The black line represents where we think we'd like grass.

#15
09-05-12, 08:09 PM
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Rotors in the front yard are Rain Bird 5000s.
Tell me what nozzles are in those 4 heads. You need to check every one.

Also what nozzles are in all the strips?

There is a sprinkler system installed in the back that is so horrible, we'll just bury it.

Why bury it? And why not use the same type heads that are in the front?

The backyard has a valve box with 3 valves. (We'll need to add 1 or 2 more.)
You may or may not. It depends.