Sprinkler system well: low and varied pressure

Discussion in 'Pumps and Tanks Well Forum & Blog. Water is life.' started by blue122, Sep 14, 2021 at 10:53 AM.

  1. blue122

    blue122 New Member

    Joined:
    Tuesday
    Location:
    Ohio USA
    Hello,

    The system was professionally installed about 17 years ago.
    2 Points 25Ft shallow wells PVC
    New red Lion 1HP 23GPM shallow well pump 40/60 switch
    Wx-101 2Gal pressure tank
    12 Zone sprinkler system

    Note: We have high iron in our well water. It turns the sidewalks a rusty brown color.

    I'm having pressure issues that started about 2 years ago on my shallow well for my irrigation system. Before the issues the pressure was around 35-40 psi continuous to most of my zones with 3-4 rotating heads and 18 GPM.

    The issue I'm having is low pressure or lack of high GPM. The pressure is running at 19 psi of pressure during a run to my larger zones of 4-5 heads and it seems to be getting worse. The heads run on those zones but the water spray is not strong at all. Now if the system is running and I pause it and let the pump run up to it's stop pressure cut off of 60 Psi and right away run the zone again the pressure will run at 30 PSI for about 20 seconds and slowly decrease to 19 psi again. I thought it was the pump so I replaced it with a pump that has a higher flow rate, but it didn't make a huge difference. All this was happening before I attempted the next fix on my list, see below.

    Next I dug down a foot and found the line to the points. The line T's to 2 points 3 feet apart.

    I cut the line and added an access point because there wasn't one. I poured down almost a 1/2 gallon of Nuwell 100 and followed that with about 5 gallons of fresh water into the wells. I let it sit for 2 hours and then hooked up an air hose to the access point I installed. I didn't send the air hose down the well. I created an access only for the air hose attachment. This way I can pressurize the wells in a closed system. It pressurized to 20PSI and held. I kept it like that for an hour. Then I released the pressure and a yellow foam rushed out of the access hole. This is what Nuwell is supposed to do. It turns red when dissolved in water and then a yellow foam when it activates with the iron and minerals on the well point.

    I then added about 5 gallons of fresh water and re-pressurized the wells again. After an hour same thing happened with the yellow foam. I added 2 gallons of water and closed the access point. Left it overnight into the next day, so roughly 24 hours. I slowly removed the plug at the access point because there was a lot of pressure form the reaction of the Nuwell. I pumped out about 100 gallons of well water with my jet pump to a hose and into a bucket so I could measure how much water I pumped out. The water started out as yellow foamy color and slowly cleared up. I added baking soda to the water coming out of the well to neutralize the acid. Everything looked like it was working great until I hooked it up to my my sprinkler system and ran a zone with 3 heads. Pressure issues again...

    New Issue - before I would get good pressure (30 psi) for about a 20 sec. and then it would drop to 19psi and hold. Now I get extremely good pressure (45 psi) for about 20 seconds and then the pump drops to 20psi for 10 seconds. After the initial drop it drops to almost zero and back up to 20 and it does this continuously (20 back to zero, back to 20 back to 0 and so on). The heads pop up and then drop back down with the pressure fluctuation. It does this continuously back and forth. I can hear the water coming up to the pump, but it seams like the wells are not producing enough water to keep the system running at a decent pressure. I tried multiple zones and had the same issue. So I went from 19psi continuous to a seesaw affect after the treatment.

    I did notice before the Nuwell treatment that the insides of the PVC lines have a thick coat of what looks like red minerals. Maybe Iron or Iron Bacteria.

    The system holds pressure when it's not in use. It held 60PSI all night. The pressure switch is working and the small 2 gallon tank is pressurized to 38psi, 2psi below cut in.

    Should I repeat the process with the Nuwell? Did I do something wrong?
     
  2. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    I would consider adding a combination pressure/vacuum gauge on the input line. If there is a big vacuum, then the points are not admitting water fast enough. If there is a low vacuum, then one of the sand points could be sucking air. I suspect you will see a big vacuum.

    The input line will be sensitive to vacuum leaks, and adding a gauge will be more connections.

    https://www.winters-store.com/contractor-4-5-30-0-60psi-kpa-1-4-btm-pct330 has a good picture of the Winters
    PCT330
    . I think the picture on https://www.supplyhouse.com/Winters...2-PCT-Contractor-Pressure-Gauge-30Hg-0-60-PSI does not match the product.
     
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  4. valveman

    valveman Cary Austin Staff Member

    Joined:
    Mar 15, 2006
    Occupation:
    Pump Controls Technician
    Location:
    Lubbock, Texas
    Like Reach says I think the point screens are clogged up. Try Nuwell tabs, chase it with 10 gallons of water, and let it sit for a few hours.
     
  5. blue122

    blue122 New Member

    Joined:
    Tuesday
    Location:
    Ohio USA
    Reach4 - I ordered the gauge you recommended and I'll let you know what I find. I do have a question... as I stated before, I installed a T in the ground pipe that had joined the wells, but before the check valve. I did this to give me access to the wells so I can drop Nuwell tablets. The points didn't have an access point before I did this. To give you a visual of this - the set up that was already there, 2 PVC pips coming from the well points coming to a T that combines them into one line. On this single line I added another T with an access point and this was the only thing I added. The line then goes to a check valve and then to the pump. The check valve is about 1.5 ft from the pump. Could the T connection I installed have a leak that will cause the water flow and pressure to fluctuate? The pump holds pressure when it's not running, but could this holding pressure be because the check valve is before the T I installed? I have a picture of the T I installed, but I don't' know how to insert it. It asked for a URL.

    Valveman - I know my original post was long, but I did state I used the Nuwell. My issue is worse now after using the Nuwell and installing the T, but I'm wondering if I have a leak at the T I installed. Pump holds pressure when not running, after pump startup the pressure is at 45PSi for 20 Sec, then it drops to 20 PSI for 10 sec, then it starts to fluctuate between zero and 20. At this time I get water when it's at 20psi and no water when it's at zero then water again and no water. Even if I wait 24 hours before pumping again I get the same scenario. There's a 2 gallon pressure tank on the system that's charged to 2psi below cut-in.
     
  6. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    If you want to drop Nuwell 100 tablets, the tablets would need a vertical drop path. I am sure you realize that the water pumped out after treatment would be harmful to plants, so that will get discarded somewhere.

    The general rule is that you want the check valve as close to the intake as practical. This might mean to use two check valves. Also, it seems to me that a full-flow ball valve in series with each path from the well points could be useful for debugging and maybe working around one sucking dry. Of course when you add anything, that introduces a new possible place for a leak.

    The best visual is a sketch. This can be paper and pencil, and then scan or photograph. Even better, it can be made with something like Microsoft Paint. PNG is a nice file format for the output of Paint if there is no photo or scan involved. JPG is the best for scans and photos.
     
  7. blue122

    blue122 New Member

    Joined:
    Tuesday
    Location:
    Ohio USA
    Reach4 - I do know the treatment is bad for the plants. I'm pumping it out to a 5 gallon bucket and neutralizing it before dumping it out. I pumped out about 100 gallons this way until the water cleared up and my PH was at 6.5. Also I do know it needs a vertical drop, but what I did was insert a few tablets at a time and chased them down with water. This did take me some time to do, but I believe I got the tablets down the wells because a few hours later I was getting gas pressure and yellow foam coming out of the access point. My question to you before I receive the vacuum gauge is will a small leak in the T I installed cause the issue I'm having or would a leak cause the loss of prime altogether. Again pump holds pressure when off, fluctuating pressure and volume when running.

    I'm getting water it's just like you're turning it on and off or something. Water no water, pressure no pressure... on and off. The fluctuation is seconds between 0 pressure and 20Psi.
     
  8. Reach4

    Reach4 Well-Known Member

    Joined:
    Sep 25, 2013
    Location:
    IL
    A small leak before the check valve will cause loss of prime. However many centrifugal/jet pumps are "self priming".
     
  9. valveman

    valveman Cary Austin Staff Member

    Joined:
    Mar 15, 2006
    Occupation:
    Pump Controls Technician
    Location:
    Lubbock, Texas
    Does sound like a suction leak.
     
  10. WorthFlorida

    WorthFlorida The wife is still training me.

    Joined:
    Oct 28, 2009
    Occupation:
    Retired
    Location:
    Orlando, Florida
    Where you suspect a suction leak, run water around the fitting(s) to see if the output changes. If it does then there is a leak. If there are all cemented PVC fittings it be rare that there is a pinhole leak. A threaded fitting such as at the cap, a little pipe dope on the threads or wrap teflon tape around the plug threads.
     
    valveman likes this.
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