Submersible Well Pump Dying?

[joshpjost]

Purchased a house last year in October. House has a well for irrigation. Not knowing anything about the well or last time it was used, I assumed all components (pump, pressure switch and tank tee, and pressure tank) were shot and needed to be replaced to be operational. I've removed the tank and associated plumbing adjacent to the 6" casing located in an 8 foot deep concrete pit. I decided to pull the pump, not knowing how deep it actually went.

Pulling pump was relatively easy. Ended up being about 150 feet deep, a Myers 1/2hp, 230V 4" submersible pump (looks about 20 years old) with 1" poly tubing. Over the next couple of weeks I put new electrical in the pit and reconnected the pump to see if it was operational. Ended up running, so I decided to throw it back down the casing, and viola, I got a decent about of water. I purchased a new pressure tank (Amtrol of course because I live right near their manufacturing site) and tank tee. Installed all components and let her rip.

Here's my problem: Pump runs constantly. Pressure in the tank tee never rises above 25psi. Pressure tank precharge is set at 38psi with a 40/60 pressure switch. I don't believe water is filling up pressure tank, which makes sense if well pump cannot overcome the precharge in storage tank. Please confirm that the general consensus is that my pump's performance is weak and the remedy to the solution is to purchase a new pump. I understand that there could be a leak that is allowing water to discharge into the casing, but I think this is highly unlikely. Let me know what you think.

 

[Valveman]

Make sure your gauge is good. I am showing a 12 GPM, 1/2HP Myers will produce 38 PSI even if the water level is at 150'. But for that pump to be able to build to 60 PSI the water in the well will have to be less than 100' deep.

 

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[joshpjost]

Make sure your gauge is good. I am showing a 12 GPM, 1/2HP Myers will produce 38 PSI even if the water level is at 150'. But for that pump to be able to build to 60 PSI the water in the well will have to be less than 100' deep.

The Myers 1/2hp pump is a 5GPM unit.

 

[Reach4]

I think you are implying that no water is being used when you are watching the pressure. If you have not done so, close the valve that is after the pressure switch and tank to be sure there is not some irrigation pipe accepting water.

 

[joshpjost]

I think you are implying that no water is being used when you are watching the pressure. If you have not done so, close the valve that is after the pressure switch and tank to be sure there is not some irrigation pipe accepting water.

Reach4, correct. I have shut off the valve after the pressure switch to the hose bib pipe. There are no other pipes other than the intake from the pump.

 

[Reach4]

Then I think you have thought of all of the alternatives, and your conclusion is correct.

 

[joshpjost]

Would a new 5GPM 1/2HP pump be capable of reaching >60psi at 150ft deep? How does one determine this? Using standard 1" poly pipe

 

[Reach4]

Use pump curves or tables. Note that 60 PSI is about 140 feet of head. So if you want to be able to pump from 150 feet, make sure that 290 feet is on the curve.

http://www.pumpsandwells.com/mm5/PDFs/B5-25GS.pdf is a nice manual for Goulds. It has not only graphs, but tables where the compensation has been taken care of. Other makers have similar manuals and similar pump capacities.

Note that your pump should take a minute or more to fill the pressure tank to avoid short cycling.

 

[LLigetfa]

I understand that there could be a leak that is allowing water to discharge into the casing, but I think this is highly unlikely. Let me know what you think.

I think you need to test out that hypothesis. Assuming no other checkvalve than what is in the pump, a simple pressure test would confirm it.