Pump Question

Discussion in 'Irrigation' started by Rainman7, Mar 8, 2006.

  1. Rainman7

    Rainman7 LawnSite Senior Member
    from NY
    Posts: 288

    I dont do these often but I'm curious how some of you guys do it. I'm doing a system supplied by a well. There is no pressure tank or switch so I use a pump start relay. The question is, do you use any safety if a valve fails to open mechanically and the pump continues to run? In the past I have used pressure relief valves set at 80psi. to dump water if there is a problem. Are there other options?

    Thanks,
    Ray
     
  2. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    You can install a flow switch that will only allow the pump to stay on if a flow is going through the main line. If you have failure of a valve to open then the flow switch will shut the pump down because a minimum amount of water is not flowing through the main line. We have one type or another on all our booster pumps.
     
  3. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Posts: 2,781

    another question a simple search would have provided hours of reading for. A less than $20 pressure switch will give you a fail safe. Set the switch to kill the pump power when the pressure exceeds X psi. Set it to come back on when the pressure drops back down into range. The wider the spread the better. A pressure tank would help prevent the possibility of short cycling, but the pressure switch as a fail safe works just fine.
     
  4. Rainman7

    Rainman7 LawnSite Senior Member
    from NY
    Posts: 288

    QUOTE=bicmudpuppy]another question a simple search would have provided hours of reading for. A less than $20 pressure switch will give you a fail safe. Set the switch to kill the pump power when the pressure exceeds X psi. Set it to come back on when the pressure drops back down into range. The wider the spread the better. A pressure tank would help prevent the possibility of short cycling, but the pressure switch as a fail safe works just fine.[/QUOTE]


    another answer that 6 seconds of reading would have prevented. Thanks for the suggestion but I was looking for an answer, not hours of reading. Isn't that the purpose of this site? During that 6 seconds of reading you would have realized I am aware of pressure tanks and switches. I was looking for other options.
    A $20 pressure switch? I guess that would work if I wanted to use the 1" poly for a pressure tank :dizzy: .
    Think I am going to look a little more into the answer Hayes gave.

    Thanks anyway
    Ray
     
  5. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    Don't mind BIC too seriously Ray. He's still looking for Auntie Em after the last tornado that blew through. :laugh:
     
  6. bicmudpuppy

    bicmudpuppy LawnSite Silver Member
    Posts: 2,781

    HMMMMM, I don't see any mention of pressure switches here. You don't need a pressure tank for a pressure switch to work. A pressure switch cuts out at x pressure and back on at y pressure. If the sole purpose of the switch is to prevent the pump from dead heading because the zone did not open, a cheap pressure switch is still the best option. Much cheaper than a flow sensor or anything else I have seen, even cheaper than a PRV.

    So, to answer your post directly, YES, I do use a safety, I use a simple pressure switch to shut the system down if the pressure exceeds a certain pressure point.
     
  7. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    Here's a picture of one of our booster pumps with a "High/Low" switch installed. The switch will only allow the booster pump to activate when the water pressure running through the pipes/pump is within a certain range. This prevents the boosted pressure from getting too high and also prevents the pump from activating when insufficient water is running, thus preventing the booster pump from burning up. We have had two occasions where High/Low switches have malfunctioned due to sporatic servicing from our electricians and the booster pumps fried and required replacing.

    We went out on this call because the booster pump wasn't activating when a site groundsworker was testing his system during one of our recent warm spells. The gate valve indicated had been shut off by unknown persons(s) thus preventing the booster pump from activating.

    La Joya Booster Pump IV-01.jpg
     
  8. ESprinklers

    ESprinklers LawnSite Member
    Posts: 39

    Hhmm... maybe I'm looking at the picture all wrong. Isn't the hi/low switch installed on what we would call the minimum flow line? And the globe valve that is blocked in, isn't that on the pump suction line? Maybe I'm just looking at it wrong. It is getting late and I've been hitting the bottle... :sleeping:
     
  9. PurpHaze

    PurpHaze LawnSite Fanatic
    Posts: 5,496

    You could be right but this is the way all our booster pumps except one is set up. They're done by a local pump company and electricians so I'll have to trust their expertise. Booster pumps technically belong to the Maintenance Department and if anything goes wrong with them then they have to repair/replace out of their budget. :clapping:

    I do remember one booster pump that didn't last very long but it didn't have anything to do with the configuration. The installer put in an "open case" pump instead of a sealed case one. It was located under the pressure tank and perhaps they figured the tank would protect it from the elements. Weather got inside the winding and fried it in less than six months. :laugh:
     
  10. Dirty Water

    Dirty Water LawnSite Fanatic
    Posts: 6,799

    Is that a welded bung on the galvi nipple that the pressure switch is on?

    I usually see that on overhead fire sprinklers, not irrigation ones.
     

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