Booster pump snafu.

Discussion in 'Irrigation' started by jcom, Apr 22, 2008.

  1. jcom

    jcom LawnSite Senior Member
    Posts: 791

    We installed a Goulds JRS5 as a supplement to a low 40 psi. install. 1" supply line and 1" POC. 1" PVB . A simple inline pressure boost.

    All zones are designed between 12-14 gpm.

    On startup, the pump works great on zone one (13gpm). The other zones will engage the relay for the pump but the pump will kick out after 1-2 seconds.

    We tried changing the kickout pressure by adjusting the screw on the pressure switch but it had no effect.

    I am sure that I am missing something but I don't know where to look right now.

    Thanks to all the pump gurus for your input.

    John:confused:
     
  2. Flow Control

    Flow Control LawnSite Bronze Member
    Posts: 1,267

    Might have a low suction pressure cutoff controller on it. Also not to be a arse, but you need to have a RP with a booster pump. PVB does not protect against backpressure only protects against backsiphonage.
     
  3. Pump has a built in pressure switch with a 30 on & 50 off.... does it kick back on?
    I think the pump must be building pressure at 50psi then cut off and it wont cut back on until the pressure drops below 30psi....
     
  4. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,041

    Combining a pressure switch and a pump relay is problematic.
     
  5. jcom

    jcom LawnSite Senior Member
    Posts: 791

    Thanks for all the info guys.

    Our PVB is on the output of the pump so that is not a problem.

    We bypassed the pressure switch and it works just fine.


    Question I have is what happens if a valve fails to open? What is the best option in this regard to shut off the pump under this scenario? An inline pressure switch maybe?

    John
     
  6. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,041

    We beat this one to death a couple of years ago. My preferred booster-pump install has no pump relay. I add a tiny pressure tank right on top of the pump, and let the pressure switch do the work.

    Backflow gets a bit complicated here, because you now have house pressure that's higher than street pressure. Otherwise known as backpressure. Lacking any specific guideline, I would use a dual check device on the suction line of the booster pump. This would be enough to isolate the pump. The PVB would then function in the standard manner. If you had the booster after the backlow preventer, then that preventer would have to be an RPZ.
     
  7. jcom

    jcom LawnSite Senior Member
    Posts: 791

    Thanks again, WB.

    The booster is only in the output to the irrigation system. The rest of the house is on city pressure.

    I don't see the need for any additional backflow protection under this scenario.

    John
     
  8. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,041

    Your mileage may vary. While there isn't any contamination in my booster-with-pressure-tank setup, the fact that the pressure is higher than the street pressure sets up the possibility of reverse flow. I would stick in a simple dual check by way of acknowledging the pressure situation. For one thing, if there ever was a later requirement for stricter measures, the dual check could be replaced by a DCVA without much change in performance. I figured it as twenty bucks well spent.
     
  9. jcom

    jcom LawnSite Senior Member
    Posts: 791

    Thanks WB.

    Will install the dual check. How about the scenario of a zone valve not opening and the pump relay has the pump on?

    John
     
  10. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 48,041

    Now you get to the heart of preferring the combo of pressure switch and mini tank. If a valve fails to open, no big deal. There was a time or two when I had a relay-controlled well pump, and I added a pressure switch to the system, with the pressure set a good bit higher than the operating pressures of the system. I figured that was better than having a relief valve blowing open.
     

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