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Help with sprinkler head placement

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Andrew77

New Member

Posts: 6

1

Monday, May 11th 2009, 3:10pm

Help with sprinkler head placement

Ok here we go. I plan on installing a sprinkler system in my front yard here in a couple of weeks. The yard is 50 ft long by 40 feet wide. There is one large tree in the upper right corner about 10 feet from the fence on the left and 20 ft from the house above. My water supply puts out about 90 PSI and approx 12 GPM. There was no special tests done except the ol' water in a bucket trick and a PSI gauge I bought from Home Depot. I plan on using MP rotators in my design.

Let me explain my design. I am a sprinkler newbie also. I read the irrigation tutorial and a lot of the archives here on the board. I was going to use two valves for the fron yard here with 1" poly pipe. There are going to be four 20 ft. corners. Two 17 ft. 180 degree rotators on each of the sides. This would make it possible to have head to head spacing on the fifty foot length. There would be one 20 ft. 180 degree rotator on the top and bottom to have head to head spacing on the top and bottom. Now, here is my problem. I was going to put two 17 ft 360 degree rotators in the middle. Problem here though is that I will not get head to head spacing to the left and right. Is that going to matter? I read on irrigation tutorial that you can exceed head to head spacing if you keep at least eighty percent of the sprinklers in head to head spacing. The website is here and it explains it better http://www.irrigationtutorials.com/sprinkler15.htm

Does this plan sound feasible or should I scrap it and go a totally different route? Are there any other ways to design it that would be beneficial? Yes, I know that I could go with the ten foot rotators but that is a little bit more money. If I left anything out just ask. All opinions are welcome. Thanks

Andy

Andrew77

New Member

Posts: 6

2

Monday, May 11th 2009, 6:46pm

On second thought

I was thinking about it and thought of a different route to take. I could take out a 10ft by 40ft section of the yard and fill it with 10ft sprinklers. I could do some triangular spacing and it would only use up 6 sprinklers. Then, I would have an easy 40ft by 40 ft. area to work with. Just an idea.

Candance

New Member

Posts: 11

Location: Nebraska

3

Monday, May 11th 2009, 11:20pm

RE: On second thought

If you put 2.5 GPM nozzled rotors in the corners and a 3.0 GPM nozzled rotor in between each corner you should be able
to cover your whole front yard. Basically three across the front and three across the back and one on each side midway.
Most rotors will shoot 25 to 30 foot or better at 90 PSI so you should have plenty of head to head coverage.
And you would be able to do the front yard in two zones with 11 GPM on each zone.

HooKooDooKu

Supreme Member

Posts: 683

4

Tuesday, May 12th 2009, 8:14am

RE: RE: On second thought

Quoted from "Candance"

...
Most rotors will shoot 25 to 30 foot or better at 90 PSI so you should have plenty of head to head coverage.
And you would be able to do the front yard in two zones with 11 GPM on each zone.

Let's keep in mind by the OPs own admition that the figure of 90 PSI and 12GPM is from a bucket test. And as he well should know from reading the irrigation tutorials that that does NOT mean he has 12GPM @ 90PSI.

I would also recomend AGAINST a new DIYer in irrigation to try to design a system that close to the limits (i.e. Do NOT design for a system to run at 11GPM when a bucket test indicates 12GPM max). Speaking as a DIY and being the "engineer" type, I would suggest to the OP that he design for a system with no more than about 8GPM MAX. Even then you can't be sure unless you've run the correct test to determine at running pressures what GPM you can produce.

Now if the issue is simply a matter of enough throw, then the MPRotators do have the 3000 series. In theory, these should shot about 30 feet. But from a practical stand point, you should design for a throw of 27 feet.

My general suggestion would be to go with MPRotators and use something like the RainBird PRS series of bodies (i.e. their regular bodies with pressure regulators built into them). It will make things much more consistant at each sprinkler head.

As for spacing, how about this...
Use 6 MPRotators 3000 series, one at each corner and one at the center of each 50' edge. This will give excelent head to head coverage along those edges. Of course that doesn't provide head to head coverage along the 40' lengths, so fill in the center of the yard with 2 306 degree MPRotators 2000 series using triangular spacing. Basically place them about 14 feet apart from each other and dial down the distance so these in the center are only throwing 14 feet rather than the 18 to 20 feet they would normally throw.

HooKooDooKu

Supreme Member

Posts: 683

5

Tuesday, May 12th 2009, 8:24am

I just reviewed the MPRotator specs here at hunter http://www.hunterindustries.com/products/mprotator/

Looks like what I was talking about fits perfectly... that if you use the PRS bodies, they should regulate the pressure to 30PSI meaning the MP3000 will throw 27', and the MP2000 will throw to 18' but can be throttled down to 13'. The total expected flow would be right around 11GPM, which in my book would be a bit iffy. To insure you have plenty of water for both the irrigation AND the house at the same time, I would split it into two zones. I would split them somewhat diagonally, with say the left side 90s, the top 180 and the left 360 on one zone, and the right side 90s, the bottom 180 and the right 360 on a second zone (or some similar pattern).

Andrew77

New Member

Posts: 6

6

Tuesday, May 12th 2009, 9:05am

RE: RE: RE: On second thought

Quoted from "HooKooDooKu"


Quoted from "Candance"

...
Most rotors will shoot 25 to 30 foot or better at 90 PSI so you should have plenty of head to head coverage.
And you would be able to do the front yard in two zones with 11 GPM on each zone.

Let's keep in mind by the OPs own admition that the figure of 90 PSI and 12GPM is from a bucket test. And as he well should know from reading the irrigation tutorials that that does NOT mean he has 12GPM @ 90PSI.

I would also recomend AGAINST a new DIYer in irrigation to try to design a system that close to the limits (i.e. Do NOT design for a system to run at 11GPM when a bucket test indicates 12GPM max). Speaking as a DIY and being the "engineer" type, I would suggest to the OP that he design for a system with no more than about 8GPM MAX. Even then you can't be sure unless you've run the correct test to determine at running pressures what GPM you can produce.

Now if the issue is simply a matter of enough throw, then the MPRotators do have the 3000 series. In theory, these should shot about 30 feet. But from a practical stand point, you should design for a throw of 27 feet.

My general suggestion would be to go with MPRotators and use something like the RainBird PRS series of bodies (i.e. their regular bodies with pressure regulators built into them). It will make things much more consistant at each sprinkler head.

As for spacing, how about this...
Use 6 MPRotators 3000 series, one at each corner and one at the center of each 50' edge. This will give excelent head to head coverage along those edges. Of course that doesn't provide head to head coverage along the 40' lengths, so fill in the center of the yard with 2 306 degree MPRotators 2000 series using triangular spacing. Basically place them about 14 feet apart from each other and dial down the distance so these in the center are only throwing 14 feet rather than the 18 to 20 feet they would normally throw.
Thank you for the help everyone. As you stated, I do know that 11 or 12
gpm is a pretty unrealistic number. I'll be keeping each zone to around
5 or 6 gpm. The mainline coming in from the street is old galvanized
steel, about 50 feet of it. I made the connection in the basement with
a backflow preventer and ran it outside. I will also be using 1 inch
poly in the yard. The plan you laid out sounds great. I started coming
up with something like this last night but was too tired to think about
it.

Andrew77

New Member

Posts: 6

7

Tuesday, May 12th 2009, 9:25am

RE: RE: RE: On second thought

Quoted from "HooKooDooKu"


Quoted from "Candance"

...
Most rotors will shoot 25 to 30 foot or better at 90 PSI so you should have plenty of head to head coverage.
And you would be able to do the front yard in two zones with 11 GPM on each zone.

Let's keep in mind by the OPs own admition that the figure of 90 PSI and 12GPM is from a bucket test. And as he well should know from reading the irrigation tutorials that that does NOT mean he has 12GPM @ 90PSI.

I would also recomend AGAINST a new DIYer in irrigation to try to design a system that close to the limits (i.e. Do NOT design for a system to run at 11GPM when a bucket test indicates 12GPM max). Speaking as a DIY and being the "engineer" type, I would suggest to the OP that he design for a system with no more than about 8GPM MAX. Even then you can't be sure unless you've run the correct test to determine at running pressures what GPM you can produce.

Now if the issue is simply a matter of enough throw, then the MPRotators do have the 3000 series. In theory, these should shot about 30 feet. But from a practical stand point, you should design for a throw of 27 feet.

My general suggestion would be to go with MPRotators and use something like the RainBird PRS series of bodies (i.e. their regular bodies with pressure regulators built into them). It will make things much more consistant at each sprinkler head.

As for spacing, how about this...
Use 6 MPRotators 3000 series, one at each corner and one at the center of each 50' edge. This will give excelent head to head coverage along those edges. Of course that doesn't provide head to head coverage along the 40' lengths, so fill in the center of the yard with 2 306 degree MPRotators 2000 series using triangular spacing. Basically place them about 14 feet apart from each other and dial down the distance so these in the center are only throwing 14 feet rather than the 18 to 20 feet they would normally throw.
Would it also be feasible to put in some more sprinklers in the middle of the 40 ft lengths? I could add some 180 degree MP2000's on the top and bottom to get better head to head coverage. This would only add about 1 to 1.5 GPM.

HooKooDooKu

Supreme Member

Posts: 683

8

Tuesday, May 12th 2009, 4:09pm

RE: RE: RE: RE: On second thought

Quoted from "Andrew77"

Would it also be feasible to put in some more sprinklers in the middle of the 40 ft lengths? I could add some 180 degree MP2000's on the top and bottom to get better head to head coverage. This would only add about 1 to 1.5 GPM.

If you want more rotors, then I would suggest removing the two MP2000's from the center and replace them with one MP2000 180 degree rotor at the center of each 40' edge and one MP2000 360 degree rotor in the very center of the yard. To divide the rotors into two circuits, I would place the four corner rotors and the center rotor on one circuit, then the four rotors on the center of each edge on a second circuit.

Here's an interesting thought. If you set the circuits up this way, each circuit covers the whole yard. So rather than running both circuits say once every four days, alternate circuits every other day.

Andrew77

New Member

Posts: 6

9

Tuesday, May 12th 2009, 5:20pm

Good idea

That sounds like a pretty good idea. Thanks for your help.

Candance

New Member

Posts: 11

Location: Nebraska

10

Wednesday, May 13th 2009, 11:50am

RE: RE: RE: On second thought

My advice was going off of over 15 years installing systems professionally and not a DIY website for homeowners.
What you propose will work but with added cost and work.
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