Locating valves

Discussion in 'Irrigation' started by muddywater, Nov 14, 2011.

  1. muddywater

    muddywater LawnSite Bronze Member
    Messages: 1,813

    We have been tracing wires for last couple days. Are these valves supposed to ping when the solenoids are bad? Found 7(all with bad solenoids), but had to do alot of pokin' because the things just will not sounds off. Once the new solenoids are installed they sound off, but I do got a loud reading when I go over a valve with bad solenoid. And I know we have been over them several times with the wand. Tried zone wires, then common. No difference. Also, we using a Greenlee 521 with fresh batteries.

    Is this what yall do, just trace wires and bring a damn pokin' rod when the solenoids are bad? or am I missing a trick?
  2. bcg

    bcg LawnSite Bronze Member
    from Tx
    Messages: 1,865

    Shorted solenoids will not scream. To find them, I trace out the common wire path and flag it, then go back to the clock and put the red wire on the zone wire and the ground on the common. Follow your wire path, you should get no feedback at all until you get past the valve, then you'll start to see the normal signal-null-signal. Back up just a little and you'll find your valve.

    Takes some practice but once you get it it's not too difficult.

    Messages: 18,668

    Best explanation in a while. I try to say the same thing and it takes 4 paragraphs. Read carefully and follow BCG to a tee.
  4. muddywater

    muddywater LawnSite Bronze Member
    Messages: 1,813

    Thanks I will try it.
  5. txgrassguy

    txgrassguy LawnSite Gold Member
    Messages: 3,083

    I agree with Pete and bcg. Also make sure you have a deck screw or a pair of splinter tweezers in your 521 case.
    Sometimes you will not be able to acquire a ground at an indoor mounted box if you need to trace from the controller. The screw or tweezers will easily fit in the ground receptacle of a house plug so you can get a decent ground needed for a reliable signal.
    Also cuts down on the rubbernecking know-it-all homeowner who might insist on "supervising" your tracing efforts. I know from first hand experience they retreat real quick when they grab the red lead on the 521 to "help" you during tracing events.
  6. txgrassguy

    txgrassguy LawnSite Gold Member
    Messages: 3,083

    Just had one yesterday, a valve locate with a "helpful" client.
    Hooked up the 521 to the common in the clock chassis (indoor mount controller), grounded the 521 to the house and tracing I went. Until:
    I hear a loud "snap" emanating from the garage immediately followed by a yell of "S-O-B!" -so I go back into the garage.
    And see the ever so helpful dude standing there shaking his right hand. Seems he just knew I hadn't hooked the 521 to a proper ground and moved the deck screw from the receptacle ground port to the hot lead side.
    And got the livingshit zapped out of his hand.
    I just stood there looking at him trying not to laugh out loud when he muttered something again so I just busted out laughing at him.
    He stood there for a moment, then shook his head and walked into his house.
    I overheard him say to his wife "That guy is really weird, knows hisshit though, but really weird".
    And the wife gave me the check when I was done.
  7. 1idejim

    1idejim LawnSite Fanatic
    Messages: 11,288

    sorry Steve but when I trace active power, I connect the transmitter to either the metal body of the panel or the building ground (rod or wire) and then establish an independent earth ground, I can then trace the power from the panel to the transformer (example), the problem with this method is that I am also putting signal on every utility that is grounded to the building.

    If you are using the grounding peg of an outlet you are doing the same thing, you are now putting signal on the entire system. The signal will travel from the transmitter on the target conductor, through the earth to the electrical ground rod up into the panel, through the house to the outlet and to the transmitter, then the signal reverses course travelling from the transmitter to the outlet, through the house to the panel, down to the ground rod, back through the earth to the target conductor which travels back to the transmitter, just to reverse its course and do it all over again, 1748 times a second.

    You'll get a lot cleaner signal by using an independent earth ground, in fact, every user manual that I have ever read states that the most important transmitter adjustment that you can make is the earth ground.

    I borrowed this from Dynatel for an example, hope they don't get grumpy;

    3.3 Place the ground rod as far away from the cable path as possible (90 degrees from the suspected cable path). Never ground to water pipe or other services in the area. The returning signal on these services may mislead the trace.

    you will find a statement similar to the above in nearly if not all user manuals

    TGG, I like and respect you, if your method works for you, that's great. Muddywater appears to be a fledgling locator and should learn proper basics first.
  8. muddywater

    muddywater LawnSite Bronze Member
    Messages: 1,813

    So when tracing a valve in this particular situation, what is a better ground? Common wire, grounding with screw driver, or receptacle?
    Posted via Mobile Device
  9. bcg

    bcg LawnSite Bronze Member
    from Tx
    Messages: 1,865

    You only want to use the common as a ground when looking for a shorted valve where you already know the wire path. When you hook it up that way, you're not going to be abel to trace the wire until after the valve you've got your red lead on.

    The point of using the receptacle is to get a good Earth ground when you can't get one with the included stake. I've never not been able to get a good ground with the stake so I've never grounded to a receptacle.

    So, in short -

    To trace a wire to a valve, get a good Earth ground.
    To find a shorted solenoid after tracing the wire path, ground to the common.
  10. muddywater

    muddywater LawnSite Bronze Member
    Messages: 1,813

    What is the trick to find a nicked wire? Patience?
    Posted via Mobile Device

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