Faulty solenoid?

Discussion in 'Irrigation' started by Fine Gardens Landscaping, Mar 9, 2013.

  1. RhettMan

    RhettMan LawnSite Silver Member
    from Texas
    Posts: 2,135

    yall broke up ?
     
  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,323

    Fimco would discover Pigtalium
     
  3. Fine Gardens Landscaping

    Fine Gardens Landscaping LawnSite Member
    Posts: 132

    Thanks for the response. I should start by admitting I'm green on the diagnosis/electrical aspect of irrigation and I need a little clarification on a couple points you made.

    I assumed that since the station comes on partially that it was receiving voltage from the clock. I wasn't aware that you could maybe only be getting partial voltage which I guess would equal partial solenoid operation?

    As to the next step in the trouble shoot:

    It's a little unclear but I think you're telling me to check resistance of the solenoid and that if it the resistance reads between 20ish - 50ish ohms that would indicate a good solenoid? The valve is a Hardie 3/4" inline valve if that helps.

    Then, if both of the above check out that would indicate a bad diaphragm.
     
  4. RhettMan

    RhettMan LawnSite Silver Member
    from Texas
    Posts: 2,135

    There are geysers on the ocean floor, but they get no credit because we cant seem them.
    __
    while im thinking baout it i also suggest Lean cuisine, Microwaveable shrimp Alfredo. 2 pcs toast. mm
     
  5. 1idejim

    1idejim LawnSite Fanatic
    Posts: 9,313

    I don't want to confuse you but the actual measurement you are seeking is amperage.

    A solenoid has an inrush current requirement and a holding current requirement.

    For example:

    A RB PGA has a coil resistance of 30-39 Ohms. An inrush current of 0.41 A and a holding current of 0.28 A.

    Without voltage drop and having a 24 vac measurement at the controller you have 0.8 A available with a 30 Ohm solenoid.

    The same 24 vac with a 39 Ohm solenoid drops to 0.615 A.

    The same 24 vac at 60 Ohms though only gives you 0.4 A to work with.

    It is easier to take these measurements at the controller than it is to get into the VB, open and replace the splices to get your information.

    If i were trblshtng this system i would eliminate the elect. first, then move on to the hydraulics
    Posted via Mobile Device
     
  6. Mike Leary

    Mike Leary LawnSite Fanatic
    Posts: 21,896

     
    Last edited: Mar 11, 2013
  7. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,323

    if the mayor of Cactus Hug discovered an element, it might get named Nilssonium :)
     
  8. Mike Leary

    Mike Leary LawnSite Fanatic
    Posts: 21,896

    O.K., I screwed it up. I meant .20 to .30 amps. A pro clock is usually good for 1.0 amps, Rain Master will handle 2.0 amps, as I would think Calsense and the
    Maxi-Coms would do. :waving:
     
  9. Fine Gardens Landscaping

    Fine Gardens Landscaping LawnSite Member
    Posts: 132

    Okay, I mostly follow but need clarification on where/how to read my measurements?

    We prefer to take measurements at controller because it's more convenient but how do we do it exactly?

    Did you mean to do it like so:

    Coil Resistance: Read from common & station power connector in ohms should be 30-50ish ohms depending on coil model

    Inrush current. Read from common to station power connector in amps. Turn on station and see how many amps there are when it initially powers on. Should be a small amount like .5 A or something (depends on solenoid model)

    Holding current: Read from common to station power connector in amps. See what the Inrush current drops to after the station initially powers on. Should be slightly less than the inrush current.

    Sorry to bring the discussion down to such a basic level but that's the level I'm at :)
     
  10. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 47,323

    Solenoid inrush currents may not be readable, unless you have some instrument that captures a peak reading. Holding current would be what you'll read. Most clamparound ammeters won't really be intended to work with sub-ampere currents, even if they'll display something. I used an analog clamparound with a special added scale of 1.5 amps that 'saved the day' more than once when there was one unknown zone that would trip the controller's circuit breaker only at times when no one was looking.
     

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