I guess I don't understand Rain Bird panel - valve hum & transformer hot

Discussion in 'Irrigation' started by gdeangel, May 20, 2013.

  1. 1idejim

    1idejim LawnSite Fanatic
    Posts: 9,662

    Your measurements are in-line so you look @ the controller. The 12vac measurement is bunk (connect your spare wal-wart for test)

    Mods fail as do any other component so swap stations or mods.
    I had a bad single in a mod the other day myself.

    As for the solenoid hum goes, 60hz hum or internal crosstalk can cause the hum. Don't worry about it.

    Nice job on the numbers
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  2. Mike Leary

    Mike Leary LawnSite Fanatic
    Posts: 22,070

    Granted, conventional wisdom has always called soleniods good if the resistance is between 20-60 ohms. However, I've found they will show problems once they heat up. My question would be be, are any valves ganged? Your ohm readings are getting close to me thinking of an open.
     
  3. 1idejim

    1idejim LawnSite Fanatic
    Posts: 9,662

    The solenoids for RB DV, DVF, ASVF, JTVF-AVB all range 42-55 ohms Boss.

    PGA, PEB, PESB, EFB all range 30-39 ohms.

    300-BPE are 28 ohms.

    That is straight from the spec book.
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  4. 1idejim

    1idejim LawnSite Fanatic
    Posts: 9,662

    You piqued my curiosity boss???

    So i ran a dry test

    20:00
    41 - R
    26.6 - E
    .216 - I

    20:15
    44 - R
    25.9 - E
    .213 - I

    20:30
    45 - R
    25.8 - E
    .217 - I

    30 minutes dry running and the solenoid was very warm but i could bare hand it.

    R - went up 04 ohms

    Let it cool for 30 minutes and R was 42 ohms.

    It was interesting to watch the results change but since this was a dry test it may be nearer to the OPs issue rather than your sceanario.

    I think the next time i will pull the plunger and see what kind of amp draw i get?
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  5. Mike Leary

    Mike Leary LawnSite Fanatic
    Posts: 22,070

    Nice math, professor, but I must not have explained myself completely, as usual, My comment concerned aging solenoids, not fresh ones. With the RM clocks, "Auto Limits" is automatically checked and a warning is issued should a high setting or low setting be detected. The warnings I've seen are "high limit", but upon firing the zone, it worked fine ( after the inrush) and a few minutes later, it failed. Replacing the solenoid always solved the problem.;)
     
  6. 1idejim

    1idejim LawnSite Fanatic
    Posts: 9,662

    You know that i wouldn't use a fresh solenoid boss, the solenoid i used is a retreival from a replaced valve and is the same solenoid that i use for all of my testing.

    As i said before, my test may not fit your sceanario but it does tell me that running the controller when the water is off may not be as bad as we might think.

    30 mins of dry run did very little to change the resistance of the solenoid and it cooled off still being within working tolarances.

    Without voltage + resistance measurements, high or low amperage measurements only tells you that something is wrong, not what is wrong.
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  7. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,017

    I still see a number of solenoid fails from zone/master valves that were powered into the winter
     
  8. 1idejim

    1idejim LawnSite Fanatic
    Posts: 9,662

    Same question i asked ML, why?

    When you experienced the failure what was the resistance? What about the wire path? Was there a short or open in the coil?

    Low resistance causes heat, higher resistance less amperage. What is the cause?
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  9. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,017

    I was just replacing the fails then, and not taking resistance measurements on them, since they were headed for a landfill.

    I replaced a newer W*M solenoid a week or so back, and I did check its resistance first ~ 30 ohms.
     
  10. 1idejim

    1idejim LawnSite Fanatic
    Posts: 9,662

    The W*M plastic thread measures 35 ohms and the brass thread measures 30 ohms right out of the box Shoes.

    I might be doing something way wrong but i don't change out solenoids unless they measure short (below 10) or open (OL or 1)
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