Stumped! Need to prime my pump.

Discussion in 'Pumps and Tanks Well Forum & Blog' started by QinVA, Jun 16, 2014.

  1. QinVA

    QinVA New Member

    Messages:
    7
    Location:
    Virginia
    I also have a plastic housing Flotec 3/4 hp shallow well pump, as I've seen on another post. It has been working for over 20 years (with maintenance, as needed). I'm new to this forum, and hoping my problem rings a bell with someone that has already had the same situation.

    This spring the pump and well worked as it always has for several days and then just stopped pumping. I could not get it to prime, and eventually found an air leak in the inch and a half PVC well pipe, and also replaced the brass check valve that had a split poppet with a new PVC CV. I also disassembled the pump. There was no distortion or clogging. I put it back together with new gaskets and o-rings, but still couldn't get the pump to prime. I back flushed the well with city water and used a manifold I made with ball valves to allow me to hook my air compressor up to the pipe and apply a high pressure surge of air to the water column to help blow out the screen - if a clogged screen was the problem. Yesterday the pump primed and I got great flow - for several minutes and then it slowly went down to nothing. If I turn the valve off, the pump builds pressure in the normal time it has always taken and turns off. But, when the water is turned back on, the water flows normally until the pump turns on and then the pressure slowly drops to nothing. This has repeated after 24 hours, and I am stumped.

    I took the pump off today and checked the well pipe with a string line and large sinker. The well pipe is 49' deep and I have a 32' water column with the top of the water at 17' down. I have no idea what is causing this once prolific well to act so strange, and don't want to throw money at it hoping to get lucky and fix it.

    One last thing: when I dug down to uncover the well pipe to disconnect the pump, there was a foot of solid clay(we live on something called the Pungo Ridge which is a natural geologic formation of talcum powder-fine clay that goes from this north end of VA Beach all the way to the southern area of the city), but below that there was a void around the well pipe that was deeper than anything I had to stick down it to try to see how deep it was. I water-jetted the dirt around it to try and fill it and couldn't get past about 12 foot depth. It now appears sealed, but don't know if I should do more or get bentonite involved?

    I will appreciate any advice, and a list of steps to take to establish what the problem is and how to determine the solution.
  2. Reach4

    Reach4 Well-Known Member

    Messages:
    2,674
    Location:
    IL
    Do you have 1 pipe or 2 going down the casing from your jet pump? Are you referring to the casing as "the well pipe", or do you have a bigger casing with a 1-1/2 inch pipe going down the casing? A jet pump with the jet in the hole has two pipes going from the pump to the well, and it can pump from deeper. The single pipe may not pump reliably from more than 25 feet from the bottom of the pipe to the elevation of the pump. So if your pump is elevated, that counts.

    You may be running out of water in the hole, or it could be that your pump is getting weaker.

    So your pump seal is buried a foot below the surface of the ground, I think you are saying.

    After all of that, I don't have a diagnosis for you. But maybe more information will help somebody help you more.


    Regarding your space around the casing, you might read http://www.terrylove.com/forums/showthread.php?57507-Ground-collapse-sinkhole-around-well-casing for information. You don't want shallow/surface water contaminating your well.
    Last edited: Jun 16, 2014
  3. valveman

    valveman Moderator Staff Member

    Messages:
    4,549
    Location:
    Lubbock, Texas
    A single pipe jet pump can only lift 24' at sea level. Since your water level is 17' before the pump is started, I suspect it is quickly pulling down to 22' or 24' and the pump can't lift from that depth. If that is the case you will need to switch to a two pipe jet or a submersible pump.
  4. QinVA

    QinVA New Member

    Messages:
    7
    Location:
    Virginia
    It's a single inch & 1/4 pipe. It's surprising to me that it would just stop working this year after so long. Everything inside looked perfect. Is there a chance the shaft seal could be leaking just enough to make this happen?

    I'm actually surprised the water is that high in the well. We are at the north end of a mid 20' elevation area with sea level less than 1/8th of a mile away.

    Any recommendations for a new seal before I spend more for an alternative?







  5. QinVA

    QinVA New Member

    Messages:
    7
    Location:
    Virginia
    All my neighbors have wells, they are all shallow, and they are all single pipe units. Mine's the only one that won't pump right now.

    The pump is on top of the tank which sits about 8" above the ground, so depth from the top of the water column to the c/l was nearly 20'. But, when I took the pump off to check depth, etc, I reconnected it with the pump sitting on the ground, and that's when it primed and started pumping. Will 2 feet make that much difference? If I take the pump off the tank I can lower it another foot and a half. Now that I think of it, all my neighbors have the pumps sitting at ground level with a small expansion tank on top.

    Thanks guys! I'm going to lower the pump, maybe even put in a little well house sunk into the ground, and see what happens. We had a dry spring and haven't had much rain yet. Could be the ground water level is low.

    I'll let you know if it works.
  6. QinVA

    QinVA New Member

    Messages:
    7
    Location:
    Virginia
    I'll bet you're correct. The time it does pump is the time it takes for the cone-of-influence to be pumped down to the point where the well can't lift the water any more.
  7. QinVA

    QinVA New Member

    Messages:
    7
    Location:
    Virginia

    I'll bet you're correct. The time it does pump is the time it takes for the cone-of-influence to be pumped down to the point where the well can't lift the water any more.
  8. Reach4

    Reach4 Well-Known Member

    Messages:
    2,674
    Location:
    IL
    2 feet can make the difference, but I don't think going from 22 to 20 feet made the difference in cavitation. Either the total rise is more than 22 feet, or the pump is weak. If the rise is more than (some number that can be as low as 25 ft -- or less if you want margin) feet, the water will turn to vapor (boil) in the pipe or pump. Whether you have a weak pump or cavitation, lowering the pump helps.

    Is "c/l" the centerline of the pump, or the centerline of the pipe to the pump, or what? If that pipe rises as it heads toward the pump, that counts.

    Putting the pump below the pipe will not help. It is the maximum of the pipe or pump heights that counts.
  9. QinVA

    QinVA New Member

    Messages:
    7
    Location:
    Virginia
    C/l is the centerline of the impeller and pump. I lowered the pump and it is a straight shot from the housing to the 90. Didn't help. After just minutes of priming, the pipe from check valve to the pump gets hot. When I check to add water during the priming op, hot vapor comes out.

    Two questions: when you are initially filling the pump and priming, how many times should that take? It has always taken 3 or 4 times of running the pump for a minute, turning it off, refilling, and doing it again.

    What makes a pump weak? Every o ring has been replaced inside. The impeller is original but it is not distorted or clogged. Is the clearance between the end of the impeller and the hole in the volute critical?
  10. valveman

    valveman Moderator Staff Member

    Messages:
    4,549
    Location:
    Lubbock, Texas
    The critical measurement is between the OD of the impeller hub and the ID of the wear ring. Maybe your foot valve is stuck closed.
  11. QinVA

    QinVA New Member

    Messages:
    7
    Location:
    Virginia
    Flotec 4012-08 Problems

    I got the well primed - finally, and it's pumping like it used to. The last thing I did was replace, or change, all the piping from pump to the check valve, and replaced the shaft seal, even though the old one looked fine.

    For those with an older Sta-Rite/Flotec plastic housing shallow well pump Model F_ 4012-08 (there are several letter designations for the same pump - FN, FJ, FP, but they all start with F), I offer the following information: After searching around for parts for this pump, driving all over our area to pick up a part that worked here, and another from there, I got on the internet today and found:

    http://www.*******.com/main/plumbin...08-or-fp4012-08-jet-pump/p-1657421-c-8672.htm .

    This Rebuild kit that Menard's is selling is cheaper than the price I paid just for the shaft seal! I also bought all the O-rings separately from wherever I could find them. If I had found this 3 weeks ago, it would have been the first thing I did and I would have been done with working on the pump itself. I hope this helps those with this discontinued model of Flotec pump. It's a good pump and has lasted over two decades. I can't even begin to estimate the number of hours it has run watering the lawn and garden, washing cars, etc. If you have a 4012 and are having problems with it, just spend the $20 bucks (plus shipping) and get the pump right.

    As for getting it primed: After trying to prime conventionally by filling the pump and pipe to the check valve about 8 times, I figured it wasn't going to happen. I hooked up a three way valve like you buy to have two hoses coming from one spigot, to a hose from the city water and into the pump using a washing machine hose with two female ends on one of the the outlets, and the other one with nothing connected to it. Turn on the city water, start the pump, and alternately shut off the city water, open the valve on the open branch, and let the pump blow out the pressure that built up. Initially, water pressure was strong for a few seconds, with air spitting out intermittently, then the pressure slowly died down to a trickle. Repeat; close the valve coming from the pump, open city water again to pressurize the pump, open the discharge from pump, turn city water off, let pressure drop and release air, and repeat again. Each time, after the initial blast of pressure from the pump, with city water off, the pressure and flow increased. After 4 or 5 of those, the pressure didn't go down when the city water was turned off, and we were back in business. It pumped for about 4 hours afterward, watering our parched lawn, and the pressure and volume built up the longer it ran. We had to close the valve down, because the sprinkler looked like it was going to take off.

    I'm still not sure what the problem was. Perhaps it would have primed if I tried this procedure in the beginning, but the pump deserved all the new pieces I put in it. The o-rings and gasket were original, and this is only the second new shaft seal - in over 20 years! I'm sure back-flushing the well didn't hurt anything either. I will definitely replace this pump with a Flotec plastic pump if this one ever dies. Growing up in a house on a well, we never had a pump last even 10 years. Part of that was that they were cast iron and the moisture in the basement led to corrosion of the pump, the tank, or the tank air volume control. So, something was always going bad. I put a Flotec plastic jet pump and precharged bladder tank in for my folks in the '70's that lasted the rest of the time they were alive - over 15 years, and only had to replace the bladder once with no other problems.

    Thanks you for the help and suggestions. I hope the information I've provided helps someone else with an older Flotec 4012-08, or a well that is being stubborn about priming.




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