Water runs downhill, right?

Discussion in 'Irrigation' started by WalkGood, May 29, 2007.

  1. WalkGood

    WalkGood LawnSite Bronze Member
    Posts: 1,910

    Situation: residential property rises up from the street about 10 feet in 60 feet to the manifold. When the zone valve is de-energized by the clock, the heads at the bottom of the hill were "running" or "leaking" for about 15 minutes without popping up. When I raised the Hunter rotaries manually they sprayed steady about 3 or 4 feet out, continuously. No master valve, BTW.

    I figured that zone valve must be leaking a bit and letting enough water thru until it was "ready" to fully stop. Customer didn't like all that water running down the street for 15 minutes so I dug out the dirt filled valve box and changed the guts of the zone valve.

    That seemed to stop the 3 or 4 foot stream from the low-lying rotary heads after the clock de-energized that zone. But the heads did "run" or trickle for about 4 or 5 minutes. Not any stream but it did trickle-flow water for 4 or 5 minutes. I explained to the customer that this much smaller amount of water is from gravity causing the zone pipes to empty, and it is not a bad zone valve again.

    Customer called the office complaining about the water trickle. Also they asked if we could "make the water trickle flow up onto the lawn and not down to the curb". (anyone have a physics-of-gravity-changing tool?)

    The only thing I can think of is that the old zone valve "housing" is a little off with the new guts (it is a gray Irritrol round screw top zone valve). Any way to prove that before I have to digout around the zone box to completely change that zone valve? Maybe just (temporarily) turn off the water feed too when that zone valve is de-energized?

    If I change the zone valve completely, and those heads STILL trickle/leak/drain for 5 minutes.... any official resources that explains that gravity is draining the zone pipes for a bit? The customer SWEARS that those heads didnt trickle flow last year after the clock shut down the zone.
     
  2. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    It's not the valve. The zone is experiencing "low head drainage" where the water in the no-longer-energized lateral lines is seeking its lowest point of relief. If you want documentation then go to the Hunter/Toro/Rainbird sites where there's documention under FAQs. Install sprinklers with low head drainage checks or add after market check valves at the sprinklers.
     
  3. Midlo Snow Maker

    Midlo Snow Maker LawnSite Member
    Posts: 183

    Please tell me your a homeowner and not an irrigator
     
  4. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    If this keeps up I'll have to get off the 'net immediately. I'm busting a gut! :nono: :laugh: :laugh: :laugh: :laugh: :laugh: :laugh:
     
  5. WalkGood

    WalkGood LawnSite Bronze Member
    Posts: 1,910

    Thanks for the info.

    This system has been running for over 4 years, and the customer claims that this has never occured before.

    Can an existing rotary head suddenly start to "weep" like this (when the zone valve is de-energized) due to age/wear? Even tho the head works fine with water pressure? They are just "regular" Hunter PGP rotary heads.
     
  6. WalkGood

    WalkGood LawnSite Bronze Member
    Posts: 1,910


    If you are talking to me, what's wrong with my post?
     
  7. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    You trust ALL your customers? How many times have you heard "it just started leaking" and there's a 10' deep hole? :)

    Hell... a brand new sprinkler can experience LHD. The water comes out the nozzle... not the seal.

    If the water stops after a short time it's classic LHD. If the sprinklers continue to leak (as in always) then you have a weeping diaphragm in the valve. It IS possible for a zone to experience both symptoms at the same time though. In that case I'd just take out a shotgun and start blasting away at the valve and heads and write up a huge invoice. :laugh:
     
  8. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,038

    Is there a master valve on this system?
     
  9. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,794

    Any self respecting irrigator should know how to install a check valve on a head.
     
  10. WalkGood

    WalkGood LawnSite Bronze Member
    Posts: 1,910


    No, I did not believe the customer. But I just needed to run this by someone else to be sure about what was happening. I figure the customer either didn't notice this at their 4:00AM run times or is stretching the truth some. Unfortunately, customers often do lie or they are stupid.

    I'm thinking maybe the customer doesn't like the big bill they already paid. The zone valve in question (that I changed the guts) was actually not even visible, was outside the too-small valve box and under 8 inches of packed dirt and grass.

    As far as looking for documentation, it's not for me. It's to show the customer that low lying heads do drain for a bit after the water is shutoff. Unfortunately customers do not always believe contractors.
     

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