pump loses prime-deep well pump

Hello,

i'm in the process of trying to figure out whats up with my pump, I have a deep well pump, the well was put in around 1964, I have replaced the pump with a new one. It is a deep well jet pump, the well itself is 2'' well casing with a 1 1/4'' inner suction pipe, and the well depth (at least the inner suction pipe is 45') not sure what the depth to the point is. I did pull up the inner casing and replaced the foot valve. It was bad and needed replacing because now I can actually prime it easily. But the trouble I'm having is this, the pump still seems to have struggles bringing in water, by this I mean when the pump kicks on the gauge will climb steadily but then it will drop and rise and continue flutuating until it finally reaches pressure and shuts off it was good for two weeks then it lost prime. I think it could be one of the following things. The point is partially plugged, either by corrosion or sand. Or that the water level has dropped in the area. Or thirdly, there is a hole in the sution pipe, even though I've inspected the pipe, i've read it could have small holes in it. Which should I try first, and how can I eliminate which one it is?
Aaron

 

First, do you have a check valve at the bottom of the foot valve? In terms of what to check first: It sounds like you might have a small clog in the foot valve. I would look in there first. This happens often with the turbulence of pulling up the pipe, sending down a new one and so on. If all of that is ok check for an air leak next. Usually you connect plastic pipe onto a barbed fitting with metal ring clamps. Every connection should use 2 ring clamps and the part where the screws are should be on opposite sides of the pipe, this ensures an air tight seal. If you have an air compressor pressure test the line while it is out of the well. If it loses pressure use soapy water on the joints or where there could be a leak. If air is leaking out it will blow bubbles. If you think the water table has dropped use a flashlight to look down the well or use a string with a weight on the bottom to measure 1) the depth of the well; and 2) the distance to the top of the water. The latter is called the static level, but keep in mind that it gets lower when there is demand on the well. Good luck.

 

Deep well jet pumps are used when the water levels are 25' or more from the surface. They require use of an ejector to help them lift water. In your case, with a 2" well casing, you would use an ejector called a packer.
From your description of what's happening, it sounds to me like the water level in the well is dropping to a point that the pump struggles to lift the water.
If you're not using a packer in the well, or a shallow well ejector on the pump, then you basically have a centrifugal pump. A centrifugal pump will not lift water and build pressure as easily as a deep well jetpump using a packer, or a shallow well jetpump using a shallow well ejector.
BTW, a footvalve is a checkvalve.
Ron