Irrigation Manifold Location

Discussion in 'Homeowner Assistance Forum' started by MTerryB, May 25, 2011.

  1. MTerryB

    MTerryB LawnSite Member
    Messages: 2

    Hello All,

    I have had a lot of fun looking through some of your posts in this thread and the Irrigation sections of this forum and I am quite impressed at the level of expertise displayed on this board. As I have a question to ask, I thought that this would be a good place to seek an answer...

    Is there any reason why the control valve manifolds are always installed below grade in a valve box?

    It seems to me that mounting above grade would keep valve wiring drier and make maintenance easier. More to the point, mounting inside the garage below the control box makes even more sense to my feeble mind...

    If I had never seen valve manifolds for heating system zone control mounted indoors, I suppose I would assume that manifolds indoors have inherent issues. However, knowing that is the norm for heating, why not for irrigation?

    The only issue I can think of is the plethora of wall penetrations for the outputs. However, a tube of good caulk and a well placed shrub outside should handle that issue...

    Note: I realize that the PVB should be outside as it might spurt when the well pump cycles...

    At any rate, I am interested in your comments.


  2. Dr.NewEarth

    Dr.NewEarth LawnSite Bronze Member
    Messages: 1,476

    You have different zones. The manifold opens and closes to activate its zone.
    I think there would be too much pvc required
  3. GreenI.A.

    GreenI.A. LawnSite Silver Member
    Messages: 2,131

    The main reason for not putting the valves inside is exactly what you posted, the abundance of holes and pipes you would have to run from the garage/basement to outside. This is sometimes common with commercial properties that will have the valves mounted inside a designated maintenance area or in a shed.

    Outside the valves can be mounted below grade or above. I have seen mounted above ground many times when down south or out west. I have never seen a professionally installed system up here with the valves above grade. If installed properly the wires will be perfectly safe from water and weather. For example I sodder the wires and heat shrink wrap them. Also we install the valve box on about 8" of 3/4 stone to help with drainage.

    The PVB should be mounted outside due the spurting off you described. If you want to mount your backflow indoors you can use a double check valve, these can be mounted in doors as the don't "spurt off" and also can be mounted below the grade of your highest head.

    Another reason not to mount the valve manifold inside is simply due to the amount of pipe. On a larger system say 9 sones. I might split it up into 3 different valve boxes. For the three furthest zones I will run one long pipe to that far box and then manifold it off for those 3 far zones. If all of the manifolds were inside I may have to run a series of pipe 200'+ to some of the zones, instead of just running one main line back there.
  4. AI Inc

    AI Inc LawnSite Fanatic
    Messages: 27,061

    1 reason for undergeround is astetics. They look like crap aboveground.
    2 reasons for outdoors
    1 as GIA mentioned , multiple holes drilled
    2 to be able to service them without needing access

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