Pressure switch cut off adjustment question;

Discussion in 'Pumps and Tanks Well Forum & Blog. Water is life.' started by Grifjc, Apr 17, 2019 at 8:59 AM.

  1. Grifjc

    Grifjc New Member

    Joined:
    Yesterday
    Location:
    Fort Worth, TX
    I am new to this forum and not sure i am posting correctly. Anyway here goes:: I have a hand dug water well that is spring fed; use for lawn watering only. Have about 2 acres so once the pump comes on it pretty well just stays on the way sprinklers are set up. I have a 3" 155Q07-150 pump Grundfos set in 2008 using 36' drop pipe per the installer's ticket. I recently realized after 8-9 years that I need to periodically check the air pressure in my 80+ gallon bladder tank! My pressure switch is a 30/50 switch although the ticket i received in 2008, when i had the tank, pump and switch new plumbing done, showed "M-1 30/55 PSI and showed p-tank 25psi" (which i have no idea what that means). Anyway I followed instructions that I found on line and drained tank completely. Sure enough air pressure was 21#'s. I aired tank up to 28#. Refilled with water and it cuts off right at 50#; but, it only cuts back on when gauge reaches the 22 -24# range?? Which means i have a differential over 20#, which i understand pumps are all set to 20# differential? Is there an adjustment that would raise the cut in pressure closer to a 20# differential or have I got other problems with the switch? Thanks so much for any feedback.
     
  2. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Maybe 15SQ07-150 or some such? That would be more pump than ideal for a 36 ft drop pipe.

    Try turning the nut on the small spring CCW, even to the extent of the spring being a bit loose. Then adjust the nut on the big screw CW to raise the cut out pressure to 50 again. About 3.5 turns is about 10 psi.

    If this does not work easily, change the pressure switch. They are cheap. Make sure the nipple to the pressure switch is clear also.

    Here are pressure switch adjusting notes:
    To raise or lower the cut-in and cut-out settings while keeping the
    differential between those two settings constant, adjust the range
    nut. The range nut is the 3/8-inch nut that adjusts the larger of
    the two springs in Models FSG, FYG, FRG, and Type G Pumptrol
    switches.
    Turn the range nut clockwise to increase the cut-in pressure and
    counter-clockwise to lower the cut-in pressure. Three and a half
    revolutions of the range nut will change both the cut-in and
    cut-out settings by approximately 10 psi.
    Adjust the differential nut if you want to raise or lower the
    cut-out setting while keeping the cut-in pressure constant. The
    differential nut is the 3/8-inch nut that adjusts the smaller of
    the two springs in Models FSG, FYG, FRG, and Type G switches. Turn
    the differential nut clockwise to increase the cut-out pressure and
    counter-clockwise to lower the cut-out pressure. Adjusting the
    differential nut will change only the cut-out setting while the
    cut-in setting remains unchanged.​
     
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  4. valveman

    valveman Cary Austin Staff Member

    Joined:
    Mar 15, 2006
    Occupation:
    Pump Controls Technician
    Location:
    Lubbock, Texas
    Also those SQ type pumps have a 5 second soft start. So even when the switch makes you will see the pressure drop for 5 more seconds before the pump gets up to speed.
     
  5. Grifjc

    Grifjc New Member

    Joined:
    Yesterday
    Location:
    Fort Worth, TX
    Reach4 ; Thanks for the excellent feedback. I will try what you said
    Reach4 I sure appreciate the great detailed response. I will try it to see what happens including making sure the nipple is clear.

    I noticed your initial comment about the pump possibly not being sized correctly for this shallow well. One of the "supposedly" better well service companies (??) in my area sent one of their people out to do the job when the pump went out in 2008. My notes reflect i was a little less than satisfied with the installer at the time so maybe my gut instinct was not off too far. All under the bridge now; but just curious what would have been a better size pump? and down side of putting in what he did. Again we strictly use this for lawn irrigation.

    Another question: What is the harm that could result to the pump from a greater differential than 20 psi? i have tried to find explanation for why there is a 20 psi standard set difference but I haven't had any luck.

    Thanks again for you feedback.
     
  6. Grifjc

    Grifjc New Member

    Joined:
    Yesterday
    Location:
    Fort Worth, TX
    Reach4 I sure appreciate the great detailed response. I will try it to see what happens including making sure the nipple is clear.

    Looks like i may have posted the reply in wrong place so i am repasting it here.

    I noticed your initial comment about the pump possibly not being sized correctly for this shallow well. One of the "supposedly" better well service companies (??) in my area sent one of their people out to do the job when the pump went out in 2008. My notes reflect i was a little less than satisfied with the installer at the time so maybe my gut instinct was not off too far. All under the bridge now; but just curious what would have been a better size pump? and down side of putting in what he did. Again we strictly use this for lawn irrigation.

    Another question: What is the harm that could result to the pump from a greater differential than 20 psi? i have tried to find explanation for why there is a 20 psi standard set difference but I haven't had any luck.

    Thanks again for you feedback.
     
  7. Grifjc

    Grifjc New Member

    Joined:
    Yesterday
    Location:
    Fort Worth, TX
    Reach4 i think i put my reply in wrong spot. hope it gets back to you
     
  8. Grifjc

    Grifjc New Member

    Joined:
    Yesterday
    Location:
    Fort Worth, TX
    Thanks Valveman; Are you saying that due to the 5 second soft start that the pressure gauge may continue dropping while the pump is already running? I thought i could hear it kick in but maybe not? Possibly pump may be working correctly and kicking in when the 30# is reached but pressure is little slowing starting to go back up? Thanks. again for great feedback.
     
  9. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Was there a reason to choose a "3 inch" pump over a 4-inch pump?
    How many GPM do you want/need? A related question is how long at a time does the pump run when you are watering for a few hours. An ideally matched pump would be running continuously.

    How much pressure do you think you need? A long-range impact sprinkler head would need a lot more pressure than a typical osculating sprinkler, and in turn a drip irrigation system needs even less.

    No harm to the pump, but it stretches the diaphragm or bladder in the pressure tank more.
     
  10. Grifjc

    Grifjc New Member

    Joined:
    Yesterday
    Location:
    Fort Worth, TX
     
  11. Grifjc

    Grifjc New Member

    Joined:
    Yesterday
    Location:
    Fort Worth, TX
    I was suckered i think. My notes reflect the guy doing the work said the old pump was a 1999 (this was in 2008) and on the short end. He told me the pumps were good for 6 -8 yrs; depending on how much sand.. I have NO sand in this well so likely did not even need a pump. My note showed (1 -1/4" pump, 6") so maybe that is what was in there? Can't believe there was a 6" in that well though; but, there is no casing this is hand dug. As far as reason for 3" i think that is what the guy had on his truck at the time and I bought off on it. Only reason for going to 3" I can think of is that was he had available.

    Can't say how much pressure i need. I irrigate about 1 3/4 ac. outside of building footprints - maybe little more; have 4 control boxes and anywhere from 5 -8 zones on each box. Pretty well takes a full day to water. I think once the watering starts and pump kicks on it stays on throughout the process. Pump will not water more than one zone at a time though. Maybe some way i could figure out how much pressure i really need.

    also FYI the Switch is a Sq.D.9013FSG 2M1

    Dumb dumb; i was busy and knew very little about water well maintenance.. learning... Thanks again.
     
  12. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Go look at the pressure gauge and see what change happens in 5 minutes, 15 minutes, 60 minutes.

    Look at your pressure gauge while watering. If it stays steady, that is how much pressure you need. If it goes up and down, note the range.

    You could take a video of the gauge, and review it by zipping ahead during the dull parts.
     
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