Water pressure is low, but pressure switch doesn't turn on

Discussion in 'Pumps and Tanks Well Forum & Blog. Water is life.' started by Leo Fruman, Nov 12, 2017.

  1. Leo Fruman

    Leo Fruman New Member

    Joined:
    Nov 12, 2017
    Location:
    Florida
    My 3 month old irrigation pump has a pressure tank and NEW water pressure switch WITH LEVER. Intermittently, the switch doesn't turn ON after water pressure drops below cut-in level (actually to "0" ). When I force switch ON and make water pressure above cut-in level, everything works great for a while. Cut-out pressure is ~35 psi, cut-in is ~25 psi. Pressure tank bladder(?) pressure is unknown. Please advise. Regards
     
  2. LLigetfa

    LLigetfa DIYer, not in the trades

    Joined:
    Feb 6, 2011
    Occupation:
    Retired
    Location:
    NW Ontario, Canada
    You need to do something about that to make it known. If there is too much pressure on the air side of the bladder, the pressure nose dives when the tank is empty which then trips the low pressure cutoff. I would increase the cut-in and cut-out settings rather than decrease the air precharge.
     
  3. Sponsor

    Sponsor Paid Advertisement

     
  4. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Irrigation only? You may not need a pressure tank or switch at all.

    With a pressure switch, you normally want at least 20 PSI differential. When you do have a pressure tank and switch, it is ideal if the irrigation uses an amount of water where the pressure does not rise to the cut-off while you are doing serious irrigating.

    Make the water pressure zero. For a submersible pump, set the pre-charge to 2 PSI lower than the cut-in. With a jet pump, set to about 4 psi below. Your symptom would be compatible with your precharge air pressure being a little high.
     
  5. LLigetfa

    LLigetfa DIYer, not in the trades

    Joined:
    Feb 6, 2011
    Occupation:
    Retired
    Location:
    NW Ontario, Canada
    Eggs-act-lee. The idea is to be high on the curve to where the pump GPM matches the usage GPM but not so high that the pump can deadhead.
     
  6. Leo Fruman

    Leo Fruman New Member

    Joined:
    Nov 12, 2017
    Location:
    Florida
    Thank you. I'll do that. What are the good CUT-OFF and CUT-IN pressure levels, if my pipes are PVC 1" and 2". I don't want to damage it
     
  7. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Note that white PVC should not be exposed to the sun for long periods. Paint or otherwise cover the PVC to protect it from the UV.

    Normally PVC should not have a problem with 80 PSI.
     
  8. Leo Fruman

    Leo Fruman New Member

    Joined:
    Nov 12, 2017
    Location:
    Florida
    Thank you guys for your comments and advises. I'll raise both CUT-OFF and CUT-IN levels, I'll make a difference ~20 PSI.
    I also would reduce pressure in PRESSURE TANK if problem would not be resolved. Regards
     
  9. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    I think step one would be to measure what the current precharge is.

    At what pressure does your irrigation system work best?

    When adjusting a normal pressure switch, the nut on the big spring affects both cut-in and cut-out. The nut on the little spring adjusts differential.
     
  10. Leo Fruman

    Leo Fruman New Member

    Joined:
    Nov 12, 2017
    Location:
    Florida
    I'm not sure how to measure current pre-charge pressure. My pump has a gauge meter attached and I can read it.
    I remember it was in my pump manual, but I read it long time ago.
     
  11. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    Drop the water pressure to zero. Measure the pressure with a tire pressure gauge. If you have more than one, see if they agree. If in doubt, a tire store can help tell you which one is right.

    When you change the air precharge pressure, that is also done with the water pressure at zero. If there is non-zero water pressure, the air pressure would always read at least that much pressure.
     
  12. Leo Fruman

    Leo Fruman New Member

    Joined:
    Nov 12, 2017
    Location:
    Florida
    Hello, Reach4. Thank you! I'll check air pressure in the tank the way you told me. I appreciate your help. Regards Leo
     
Similar Threads: Water pressure
Forum Title Date
Pumps and Tanks Well Forum & Blog. Water is life. Pressure Tank & Water filtration system configuration Thursday at 10:39 AM
Pumps and Tanks Well Forum & Blog. Water is life. Pressure Tank Has Water In It But It Appears To Still Be Working.. Apr 6, 2019
Pumps and Tanks Well Forum & Blog. Water is life. Yearly service/ water pressure Mar 27, 2019
Pumps and Tanks Well Forum & Blog. Water is life. Varying Pressure after Water Softener Install Mar 21, 2019
Pumps and Tanks Well Forum & Blog. Water is life. Low house water pressure looking to boost it Feb 19, 2019

Share This Page