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  1. #1
    Join Date
    Sep 2018
    Posts
    7
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    Pilot operated solenoid...

    Hey all,

    Has anyone else ever dealt with a pilot operated solenoid for cooling tower make-up water?
    While troubleshooting my empty tower i found the solenoid worked, but would only allow water to trickle out at the tower. The run had about a 25ft rise. When i ohm out the coil i noticed the resistance value didn't add up to the watt and voltage rating on the coil plate. I took the chance and changed the coil. Turns out the coil would fail and close when the water line completely filled..

  2. #2
    Join Date
    Aug 2002
    Location
    Southold, NY
    Posts
    17,750
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    Whats the water pressure at the valve?

    Is it above the minimum for the valve?

  3. #3
    Join Date
    Jun 2008
    Location
    Windsor, Ont.
    Posts
    758
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    A pilot operated solenoid valve utilizes water pressure to open the main port of the valve, chances are if it used to work and no longer does the valve is gummed up internally.

    In regards to a wattage rating on a coil, it is an inductive circuit and ohms law won't work. If you measure the amp draw and multiply that by the coil voltage it should get you close, coil resistance will only tell you if the coil will conduct or not.

  4. #4
    Join Date
    Sep 2018
    Posts
    7
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    Thread Starter
    Had 20-30psi at the supply to the valve. I didn't see a minimum water pressure rating anywhere. The internals of the valve were clean as can be. Changed the coil and it worked fine. Amp draw was about 0.15amps, it should be about .05 amps on a 6watt coil?

  5. #5
    Join Date
    Sep 2018
    Posts
    7
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    Thread Starter
    Had 20-30psi at the supply to the valve. I didn't see a minimum water pressure rating anywhere. The internals of the valve were clean as can be. Changed the coil and it worked fine. Amp draw was about 0.15amps, it should be about .05 amps on a 6watt coil?

    Or if i use the measured resistance (260) multiplied by the measured amps (0.15) it should add up to supply voltage or close?

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