Replacing old well pump, some newbie questions

[bhil923]

I need to replace my well pump, and wanted to make sure that I am thinking things through correctly. I have gone through websites, forums, and videos to try to make sure that I understood things before bringing up any questions. I bought a 3/1 foreclosure (may change to a 3/2), thus had no info on the well, and it would not pump any water up. After some testing I enlisted some friends to help me pull the pump. The pump is a 4” 8gpm 3/4hp 2-wire 230v Pentair/Myers, and the well is 6” diameter. The pump sits at 237’ with the static water level at 46’ leaving 186’ of water above the pump. The pitless connection piping comes into the basement at about 2ft above the tank bottom.

I want to make sure that I get the best out of replacing the pump, and had a few questions to determine if my thinking is correct and if I am missing anything.

I attempted to calculate the Total Dynamic Head with the assumption that the pump level is at 100ft (I did not have this info), note there is a sediment filter before the pressure tank, but I could not find the friction loss for it. My calculation is: Elevation Head of 100’, Friction Head of 8.8884’ (2x90º elbows and 267’ of 1-1/4” poly), Pressure Head of 138.6 (60PSI) for a Total Dynamic Head of 247.4884. giving this assumption at 8GPM (sticking with what the existing pump was set at) I calculate I need a 3/4hp pump which is what was in there.

I am planning to stick with 230v, the 1-1/4” poly, sediment filter and the single check valve at the pump. I plan to change to a 3-wire with a CSCR control box, and add a CSV before the pressure tank (20gal). I’ll also add a torque arrestor at the pump (none were installed before) and spacers at 10ft intervals.


So my questions are:

Is it safe to assume that the original pump is correct (8GPM 3/4HP)?

Would only having the check valve built into the pump be sufficient?

Are there any calculations that need to change because of the installation of the CSV?

Would changing to a 3-wire and the CSCR help to prolong my installation, as I have read?

Is there anything else you would recommend I do while I have everything removed, or any changes to my ideas?



Thank you very much for your help, I hope this all actually made sense.
-p

 

[Valveman]

You did a good job of figuring. Sounds about right. A 10 GPM, 3/4HP is best at that depth and pressure. The only other calculation you need to see if it will work with a CSV1A is max pressure. Max pressure on the pipe prior to the CSV1A will be 148 PSI, which is perfect. You don't really need a 20 gallon size tank as a 4.5 or 10 is plenty with a CSV, as comes in the PK1A kit. But the CSV will work with any size tank. You also do not want to use torque arrestors or stand offs up the pipe. Just use double jacketed wire and tape to the pipe every 10-20 feet with regular electric tape. A CSCR control box is great, but maybe hard to find and not really needed. Just a standard CS control box is all you need. And yes, only one check valve at the pump, as any other will cause problems.

 

[Sponsor]

 

[Reach4]

I am planning to stick with 230v, the 1-1/4” poly, sediment filter and the single check valve at the pump.

What does that mean? Sediment filter at the pump? I won't call Shirley, but....

OK, probably not what you meant, but just to be sure: no cartridge filter or normal sediment filter before the pressure switch.

Remember to replace the o-ring on the pitless. That will be seeing a lot of pressure. I would use Molykote 111 on that o-ring.

Torque arrestors can be negatives.

 

[bhil923]

Thank you guys! I didn't think about the o-ring, to be honest. Any reason why I shouldn't do any spacers, or the torque arrestor? I figured the spacers just help when lowering the pump down from having the chance of hitting sides, and the torque arrestor from the pump turning the pipe in the well when it kicks on. I am guessing that perhaps the low HP, with poly, makes the torque arrestor not necessary? Again, thank you very much, I'll start ordering things this week and get this project out of the way.

 

[Valveman]

Use double jacketed wire and no torque arrestors or standoffs. They are just extra stuff that can cause your pump to be stuck in the well.

 

[bhil923]

I want to say thank you to everyone, I took my time to source all of the equipment and plan everything out, and then waited until spring/summer so I would be able to easily hand dig the line from the house to the well head. I made a few mistakes along the way, but everything is working to the manifold and no leaks! Now I get to re-plumb the house since this foreclosure was never winterized. Cheers!