Irrigation Question

Discussion in 'Irrigation' started by mojob, Aug 17, 2006.

  1. mojob

    mojob LawnSite Senior Member
    Posts: 515

    I'm hoping someone out there can shed some light on this. Ive got a zone that when turned on by the clock, it has very little pressure. I found a valve box nearby with three 1"-24v valves on the same manifold. Thinking the solenoid was bad, I turned the solenoids counterclockwise one at a time to see if the zone would come on with full pressure. Well, it did. When the valve in the center of the manifold was manually opened, the zone would function properly, but it would also come on (with low pressure) when the third valve was opened (with the others closed). All the zones worked properly when I took over this account and I haven't changed anything. Any ideas?
     
  2. Mr. Vern

    Mr. Vern LawnSite Senior Member
    Posts: 632

    The first thing I would do is swap the solenoid on the problem valve and see if the problem moves (don't change the wires). If the problem moves with the solenoid, then you have eliminated the mechanical section (valves,etc... this is what's called "half splitting"). Now if the problem moved, the next step is to wire in a new solenoid if you have it, or if you don't have one you can switch the wires with one of the working units. This should narrow it down to either the solenoid or the timer/wiring. If you follow this approach, you should be able to nail this down in no more than 5 minutes. Hope that helps.
     
  3. mojob

    mojob LawnSite Senior Member
    Posts: 515

    Yeah but why do two valves operate the same zone when you turn them on manually?
     
  4. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    Unless the lateral lines are tied into two different valves they shouldn't.
     
  5. Mr. Vern

    Mr. Vern LawnSite Senior Member
    Posts: 632

    Is it possible that when the one valve is opening that it is dropping the pressure on the rest of the manifold enough to cause the other one to leak?
     
  6. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,006

    What's the brand of the valves? I have seen that "low pressure causes a valve to stick open" phenomenon on certain brands, especially one made in Colorado.
     
  7. mojob

    mojob LawnSite Senior Member
    Posts: 515

    The valves have Hydro Rain stamped on top.
     
  8. I have seen the white Hydro Rain valves and they are the same as a Hardie 205 valve. The Hydro Rains are about 15 year old valves. A Low pressure situation on a 205 is caused by the diaphragm not being able too fully open.
    Replace the diaphragm. I changed 5 Hydro Rain diaphragms about 2 months ago with low pressure problems.
     
  9. mojob

    mojob LawnSite Senior Member
    Posts: 515

    I'll have to go back and see if another zone comes on when I open either of the two valves. It's a big apartment complex so it is possible that another zone was coming on and I just didn't see it. Thanks for all the input and keep it coming.
     
  10. mojob

    mojob LawnSite Senior Member
    Posts: 515

    These have a black top if that makes a difference. The irrigation supply house wasn't familiar with the brand. They do sell Hardie and Irritrol so I might be in luck. Do you know if the solenoid is the same too?
     

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