well pump?
I have worked with Groundfos submersible pumps in environmental applications and there can be a number of mechanical reasons for low output.
I assume that you have no top side issues with the accumulator tank and pressure switch and that you have already checked this equipment.
Down hole issues pretty much indicate that its time for a new pump especially if its a very deep well. The cost of a rig doesn't justify returning old equipment down hold. So don't try just replacing just the pump end and reuse an old motor that could burn out. You might get away cutting cost and reuse old equip with a shallow well submersible that you can pull by hand. Its not work the risk if you have to use a drill rig to pull it.
Iron build up within the impellers is a common cause especially if there is high iron content. The impellers get clogged and also become out of balanced. Eventually the out of balance rotor starts wobbling and wears the seals between each stage. The upper stages go first and in extreme conditions the wobbling rotor causes a failure of the motor shaft seal resulting in water entery into the motor and total failure with an electrical fault.
Impeller wear can also be caused by silt entering the well. It acts like an abrasive and wears away the impellers.
The next likely cause is a hole in the riser pipe or a fitting this allows water to spray back into the well. A leak can be below the water surface so you won't necessarily see of hear it in the well casing when the pump is running.
Easy stuff first: Check the supply voltage while the pump is running, and measure the electrical current draw. if all is within spec, you may have to pull the pump out of the well and do some checks.
Is there any water coming out of the pipe at the surface? If not, the inlet screen or foot valve may be clogged, or the pump is not submerged in water. If its just low pressure but water is being pumped, look for a water discharge somewhere. Shut off any lines going out from the pressure tank, and check for leaks around the tank and back to the well head.
If it is new...
Look up the specifications.
Does it have more discharge head than the total depth and height above ground, plus a reserve that is the pressure, though less the pipe pressure drop? Pipe size? Thus pump discharge head in meters for the flow in litres per minute etc., less pipe pressure drop in meters of head and height from water to the top end of the pipe in metres leaves the pressure in meters of head, where 10m = 1 atmosphere.
The voltage drop to the pump depends on the wire size and length. Less than 2% of the voltage at maximum current is good.
Make sure air can get to the water surface freely, and the pump is truly submerged. Also no bubbles in the discharge. Also the intake is not restricted by leaves, dirt etc.
The two links provide a check on pressure drop and voltage drop.
be sure you've installed right pump by its capacity. If not check the inlet pipe foot valve. Clean the pipes. Remove air if there is present. By loosening the bolt screw again tight it.
why do I have low water pressure on a drilled , submersible ,
well pump?
