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NC (normally closed) PSR

Discussion in 'Irrigation' started by sp00kster, Apr 7, 2006.

  1. sp00kster

    sp00kster LawnSite Member
    Messages: 2

    Any one no where I can locate a NC (normally closed) PSR (pump start relay) or a standard NO - PSR that can be modified to a NC status?

    I need to figure out how to shut off a chlorinator when sprinklers come on. Chlorinator is 220vac liquid injector model that is wired directly into the well pump switch. So it runs whenever the pump runs - regardless house or irrigation. My thought was an attemp to reverse the normal use of a PSR wired to the sprinkler controller. So instead of using the pump start relay sending a start signal to the 220vac well pump but rather a stop signal to the 220vac chlorinator. My problem is that standard PSR's are normally open I need to either find one that can be modified to be normally closed or possibly use a standard model in conjuntion with a DTDP (double throw double pole) relay as to reverse the normal usage.

    Any other ideas or help would be greatly appreciated.
  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,579

    They don't make normally-closed pump start relays. They never will. You will have to use a relay with normally-closed contacts, or more likely, the DPDT relay you already mentioned.
  3. Dirty Water

    Dirty Water LawnSite Fanatic
    Messages: 6,794

    I would replumb the chlorinator to isolate it (with a proper backflow) from the irrigation system, shouldn't be hard.
  4. greenhorn123

    greenhorn123 LawnSite Member
    Messages: 52

    but i dont think his problem is chlorinating the irrigation water, that would be easy. i think he doesnt want the chlorinator to run while the irrigation is running.i would call the company that makes that thing and ask how you can power it with out wiring it with the pump.
  5. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,579

    Is this thing a flow-driven venturi device? Or some sort of positive-displacement pump, which you would still want to lock out.
  6. sp00kster

    sp00kster LawnSite Member
    Messages: 2

    Not venturi model - chlorinator is set to inject into the flowing potable water side where solution is carried to a retention tank. Standard setup is to wire into pump switch and unable to isolate plumbing for irrigation for many reasons without an independant pump.
  7. Mdirrigation

    Mdirrigation LawnSite Gold Member
    Messages: 3,754

    Ihave done what you are asking for the same reason, the part is available at your local heating and airconditioning supply house . I forget the exact part number but they have them that will work normally open or normally closed depending how you wire it . I built a box usung off the shelf electrical parts and made a pigtail so that when the sprinkler went on it shut off the electric to the conditioning system , when the sprinkler was done the mastervalve shut off and the electric was restored to the conditioner.
  8. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Messages: 50,579

    Sometimes such a relay will be called a "contactor" - you have to notice how much current the coil will draw, since it may be beyond the range of some solid-state controllers. One could always interface a tiny 24vac relay between the controller and the power relay, but those can be hard to come by, from either irrigation or electrical supply houses. Probably easier to just upgrade the controller, if need be.

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