you can't fix it till you find it

Discussion in 'Irrigation' started by 1idejim, Oct 13, 2011.

  1. 1idejim

    1idejim LawnSite Fanatic
    Messages: 10,896

    Yesterday I broke an unmarked lateral, yep barely snagged it but, the water was a gushin fer sure.

    The disconnect was "nowhere to be found" so the general went for the purveyor and I went for "Dexter", my pro-800.

    I set "Dexter" up over the main, turned the broadcast mode on and began searching like I had better sense, no luck.

    I turned to leapfrogging the mainline and searched all likely spots for a valve box. Now, these are big city water boxes just like you might find in Texas or Florida and I have seen a few so I knew what I was looking for, still no luck.
    Next, I set up over the disconnect for the fire hydrant and I wasn't going with the signal, maybe 50' and couldn't detect signal slope on one side of the trace, I was pissed, "Dexter" let me down.

    By now the purveyor had been on site for a few, told us that they had no clue of where the meter box could be but he was goin to try to throttle the water down at the main tank, shutting down the subdivision.

    I ran back to the truck, grabbed the magnawand ID-1200 and swept the areas of interest and sure enough it went off directly over a pile of rocks, I hollered at he guys to grab some wrench's and start moving rocks.

    The rest is history, maybe not as good a read as some but hopefully better than others.

    The main reasons that I wanted to post this little mishap are
    1. even though I did a pretty thorough sweep and visual pre-excavation search of the property, I got caught with my pants down.

    2. The reason that "Dexter" wouldn't perform when set up above the F.H. shut off was 2-fold. First was that the trace wire was twisted for about 2', this gave it cancelling properties similar to a telephone twisted pair.

    3. Since i was over a twisted pair the signal was weaker and coupled to the wire it travelled at 50% strength each way. "Dexter" didn't let me down, I let "Dexter" down, the 800 did what it should have done and I should have known why I couldn't get a signal.

    4. Having a totally different type of locator on hand made a ton of difference, I really wish that more of you guys had both wire and pin locators. I picked the metal trap-door in the lid up and was able to shut down the freeflow.

    5. I work around "hot" utilities often, I feel confident doing so because I use my locators to aid in damage prevention but there is always something that can go wrong and ruin your day.

    1idejim-i breakshit:hammerhead:



  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,059

    how does a single trace wire become a twisted pair?
  3. txirrigation

    txirrigation LawnSite Senior Member
    from Texas
    Messages: 977

    It's a long story about my ex wife...

    Good find Jim, sometimes I am on site at large comm. properties and wish I had your knowlege in my back pocket.
  4. Mike Leary

    Mike Leary LawnSite Fanatic
    Messages: 23,019

    Great recovery, Jim.
  5. NC_Irrigator

    NC_Irrigator LawnSite Bronze Member
    from NC
    Messages: 1,444

    I keep my metal detector on the truck at all times as well.
    Schonstedt ol' trusty.

    Use it several times a week.
  6. Sprinkus

    Sprinkus LawnSite Silver Member
    Messages: 2,282

    Good job in figuring it out!
    So many guys these days would just give up.
    Locates aren't always the easiest thing to do and occasionally something gets missed.
    I remember a job on a private property a few years ago where I did all the locates, phone, electrical, gas. outdoor lighting, water lines. I got everything marked out and then proceeded to trench right through the irrigation mainline that I had installed the previous year. :cry:
    Don't kick yourself to hard for it.

    Oh yeah, I couldn't resist:
    Hmm, I usually use shovels to move rocks but it does look like they were fairly large rocks. :)
  7. 1idejim

    1idejim LawnSite Fanatic
    Messages: 10,896

    when a length is doubled and twisted together. great idea for the installer and his intent is that when a signal is applied the tail is cut and signal applied to one side or the other and not both.

    my original search began with the 800 in broadcast mode to allow me to trace without making any direct connections.
    i retraced the line later and found that by moving the transmitter a couple of feet beyond the junction and was able to trace the wire without much issue.

    being a pretty curious guy boots, you can appreciate that most of the locating that i have been doing with the 800 has been in broadcast mode. i am pushing the 800 as far as i can, so far i am pretty happy, i am finding a few valves with wireless and tracing pipe and utilities for damage prevention fairly well.:)
  8. 1idejim

    1idejim LawnSite Fanatic
    Messages: 10,896

    oh yea and btw, this was a favor for the general and his plumber (we're all friends) and will only cost me $42 + tax for the coupling and a 100 mile drive for the parts since we're not in poly country. :hammerhead:
  9. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,059

    next time, be prepared


    Messages: 18,668

    Why use the wireless mode on tracking down valves when you can knock it out faster just doing it the traditional way?

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