Discussion in 'Irrigation' started by dbell6, Jan 31, 2006.

  1. dbell6

    dbell6 LawnSite Member
    from Tulsa
    Posts: 12



    Sorry for the long post, but I need some help.

    I recently installed my second sprinkler system and I am having pressure problems.

    I have a ¾ in meter and ¾ in SCH 40 pipe running all my heads. I am running 8 Rain Bird 1800 Series heads with MP-3000 Rotors. These rotors should put out a max radius of 30’, I am getting about 7’.

    Do I just have to many heads on one zone? If split the zones, is there anything else I should install to guarantee I will have pressure?

    Rain Bird recommended I us a PRS-Dial and this would fix the problem. The only down side is I have DV Valves the will not fit “Great Tech support”.

    My local Ewing dealer said I should split the turn it into two or three zones. Two would be manageable, but three would be too much work.

    Should I install a booster pump?

    My GPM is 7.69 and my pressure is 76 lbs. This is all from an exterior faucet.

    Also I have 38 1800 Series heads and about 1500” of ¾ pipe.

    Please help
  2. Ground Master

    Ground Master LawnSite Senior Member
    Posts: 505

    Hooking into an exterior faucet would be the first problem

    1500' of 3/4" pipe is also a problem, your losing about 5 psi for every 100' with 8gpm.

    If you add up all the pressure loses, I'm surprised you even get the heads to pop-up.

    Try capping all but 1 head and see how that head sprays
  3. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,712

    How many zones are you running now? You're supposed to know the exact flow and pressure you have, before you lay out the zones, using the flow rate information on the sprinklers you want to use. And, as already mentioned, you are supposed to be taking the sprinkler water from just after the water meter, so you don't have extra pressure losses.
  4. dbell6

    dbell6 LawnSite Member
    from Tulsa
    Posts: 12

    My post mistake. I am hooked up to the meter! I just measured the pressure and gpm at the exterior faucet. I was planning on just capping off 4 of the 8 heads. I made the mistake of using the Rain Bird Design service. Based on the information I provided, they designed my system.

    No I have this pressure problem.

    When my system was first installed I was using Rain Bird 15F Heads. I was told to try the MP Rotors to fix the problem, which ii didn't.
  5. Broker

    Broker LawnSite Senior Member
    Posts: 382

    If your specs of 70 some static and 7 some gpm out of a spicket (usually off of 1/2" line) with a 3/4" meter and piping........... I would adjust your nozzles accordingly and most likely you will have to change your design alittle. But you may have a 2%er job on your hands. About 2 percent of our installations every year have pressure/flow problems even though we pretest before installations. For example if you get a high pressure reading of 78psi at a spicket and design according to pipe/meter for flow and you have a pressure/flow problem it may end up being a kink or blockage in the service line (more applicable for areas that run soft copper service lines) or blockage/problem with meter which you can test by just taking the meter out and putting a piece of pipe in its place. Also make sure the ball valve at the road is turned on all the way. Get a key and turn it all the way off that back on all the way. A sign that there is a blockage or kink in the service line/meter is the zone might turn on with a little more pressure then die down after it starts running. Every year 2-4 houses we install have this problem. Solutions we have had to use. (backhoe the frontyard following the service line until you locate the kink, extra fun when the house has just been sodded, booster pump (just a bad band-aid), cut up some zones.
  6. Ground Master

    Ground Master LawnSite Senior Member
    Posts: 505

    How long are your pipe runs from

    1. The point of connection to valve manifold


    2. from each zone valve to the first head on the line?

    and is the pipe all 3/4? like you said originally?
  7. dbell6

    dbell6 LawnSite Member
    from Tulsa
    Posts: 12

    The longest run would be about 400'! Yes all the pipe is 3/4" Schedule 40
  8. Yikes....8 heads on a 3/4 sch 40 line? 8 full mp3000's? According to their charts from the 55psi the grey mp3000 uses 4.27gpm...x 8 heads...= 34.16 gpm .....not gonna happen.

    I'm just assuming you are using the Full's....because you said in a previous post that you were using 15-F...and they recommended the MP3000's.....

    If the heads are spaced at 15 feet...I recommend using the MP1000's...they will use slightly less than 1 gpm...and they MIGHT work....they might not.

    give us some more info on how these heads are set up...are they all in the middle of the yard? i.e. 360 degree sprays?

    help us help you.
  9. dbell6

    dbell6 LawnSite Member
    from Tulsa
    Posts: 12

    There are two main lines that divide the front yard that contain the 8 heads, 4 per line. I am going to plug 4 tonight and see how this works.

    My MP Heads are Full Circle!

    Hope this works
  10. But do all 8 run on the same zone?

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