Solenoid Valve Timer

Discussion in 'The Projects Forum' started by mrtyrel, Oct 6, 2012.

  1. mrtyrel

    Thread Starter New Member

    Oct 6, 2012
    Hi all,

    I'm in the process of building a timer for an irrigation system. I am using a 24 volt solenoid valve that I pulled from an Orbit timer. The Orbit runs on two AA batteries (3v). The board inside the Orbit timer has a 1000uF capacitor @ 6.3v and a second 2200uF @ 25v, which I am assuming is used to charge the solenoid valve. This is where I get stuck and would be very grateful if someone could at least point me in the right direction if not help my solve the problem. I have looked for a schematic online but to no avail.

    Thanks in advance,

  2. JohnInTX


    Jun 26, 2012
    Its a two-solenoid pilot-operated diaphragm valve as described in the patent. To save battery life, the controller pulses one coil to open the valve and the other to close it.

    I haven't buzzed out the controller but based on your description, I would suspect it might charge the big cap (to what volts, I don't know) then dump it into the particular coil to transfer the internal diaphragm inside the valve. That would reduce the current requirements of the batteries. Also, pulsing the dual coil means that it doesn't have to continually energize the coil to run the water, only when changing states. You can try this out by turning it on and pulling the plug from the controller, the valve will stay on.
    mrtyrel likes this.
  3. mrtyrel

    Thread Starter New Member

    Oct 6, 2012
    Thanks John,

    That's exactly what I figured. The problem I am having is getting the voltage up high enough to pulse the coil. I've tried various experiments with the the same capacitors on a breadboard at 6v DC but haven't been able to get the voltage up to 24v. If you have any ideas, as always, they would be much appreciated.

  4. Bernard

    AAC Fanatic!

    Aug 7, 2008
    Maybe a joule thief is at work?