Booster Pump Tech

Discussion in 'Irrigation' started by PurpHaze, Apr 22, 2007.

  1. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    While doing repairs at a site last week I had to do some reasearch on a system because we have no asbuilts from the installing contractor. Discovered that the booster pump was installed without a "flow cutoff", "hi/low" switch (various names). This system is only about three years old, is on one of our new elementary school sites and there are two other sites with the same set-up... domestic water source boosted for the large field sprinkler zones.

    When the field controller comes on it also activates the booster pump through the pump start relay. Problem is... if there is no water going through the system due to someone shutting down a zone valve, an isolation valve or the backflow device the booster pump will still run the entire duration of the zone/system program without water going through it. This can lead to the booster pump motor burning up, requiring expensive repairs and/or replacement.

    Even though the systems were designed by an irrigation consultant it's possible that the consultant is not up to speed on booster pumps. The info was turned over to the head district electrician who is looking into installing switches on each pump. Good thing is... there are two new school sites in the final design stages where a change order was initiated to insure that their booster pumps are installed with the switches.

    Four Creeks Booster Pump IV-01.jpg
     
  2. Wet_Boots

    Wet_Boots LawnSite Fanatic
    Posts: 46,482

    You mean paddle switches? For indicating a no-flow condition?
     
  3. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    Basically... there's different types.
     
  4. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,799

    My ideal booster pump set up would be a PSR with a flow switch connected to the 24v line to the PSR.
     
  5. bdb

    bdb LawnSite Member
    Posts: 74

    http://www.munrocompanies.com/content/view/29/84/

    They make the Smart Box which has a pressure sensor that shuts off at low pressure. Also have a thermal sensor to shut off if there is no flow when the pump cavitates and gets too hot. Those are economical. They also make VFD controllers.....that is my ideal booster pump but it costs a bit more. In the long run you should have less problems. Any three phase pumps you can put a VFD control panel on.
     
  6. Valveman

    Valveman LawnSite Member
    Posts: 53

    Purphaze, the picture of the booster pump shows that the eccentric fitting on the suction side is upside down. This can cause air to build up at the high point. When the air bubble is big enough, it will be sucked through and the pump will loose prime.

    Also, we have a lot of school and other type irrigation systems with booster pumps that use Cycle Stop Valves for the control. The CSV with a small tank and pressure switch, works better than VFD controls, flow switches, and pump start relays. See this link.

    www.cyclestopvalves.com/video/pbs_2006-dsl.wmv



    Thanks
     
  7. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    I'll leave this to the "skilled trades" guys in our district since I'm just a "sprinkler jockey." :)

    www.cyclestopvalves.com/video/pbs_2006-dsl.wmv

    Very interesting video. Thanks.
     
  8. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    I'll leave this to the "skilled trades" guys in our district since I'm just a "sprinkler jockey." :)

    Very interesting video. Thanks.
     
  9. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Posts: 2,781


    Lose prime? on a city water booster pump?
     
  10. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,799

    Perhaps there is a LOT of air in the water :laugh:

    I can see what Valveman is saying if there was no positive pressure on the pump...kinda, and I'm still doubtfull that a pump that large would lose prime from a small bubble like that. But when you have positive pressure coming in, then I'd be impressed if they could get that pump to lose prime :)
     

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