Help with a new Deep Well system.

[Runnin4]

Hi all,

Just had a new well drilled and we're in process if figuring out the new pump system.

The well specs are:
645' deep
300' static water level (driller dropped a stone down and counted it out, 3sec so apparently it's 300'. Is this standard practice? I'll be measuring this with a a washer and string to verify)
Metal Casing 6"
50gpm at 645'

Called a couple of well installers around the area. The 3 that quoted (out of the 5 we contacted) all 3 came back with a 1.5hp pump, 400' 1" pvc, 52gal (one said a 44gal) pressure tank. 1" PEX going from the pitless adapter to the pressure tank inside the house.

In my findings online, this seems like 1/2 the amount of power that is needed for this deep of a well, am I wrong?



From what I've researched, my calculations are as follows:
static water level 300'
pressure tank 139' (60psi) (using a 40/60 switch)
horizontal run from pitless adapter to inside the house to pressure tank 115'/10 for friction = 11.5'
Total Head = 450.5 (correct?)

So with 450.5 Total Head, I should be running a 3hp pump.
And if I'm doing this myself, I would run 1.25" poly pipe roll sidr7 rated at 250psi down the well 450'. Then 115' horizontal from the pitless adapter to the pressure tank inside the house. I already have a 3" pvc sleeve ran for this.

Other notes:
- use 8g wire
- only use 1 check valve (the one that comes inside the pump)
- use a torque arrestor about a foot above the pump
- poly safety rope
- Pressure Tank 119gal.

I'm still looking for the best quality pump brands and starter box.




What do you all think?
I just can't seem to understand how the 1.5hp pump would function with a 4 bath home which I estimate at 15gpm usage would work?


Thanks again all for the help!

 

[Reach4]

1. No need for a 15 gpm of usage. A house usually peaks at about 7. The exception is that some backwashing iron filters may need more than 10 gpm. I guess a fire sprinkler system could be another exception.

2. A normal10 gpm pump can usually put out more than 10 gpm at cut-on pressure.

This is a table form of describing a particular 10 gpm pump series.

 

[Sponsor]

 

[FredG]

Skip the safety rope, and torque arrestor. 450’ on poly is pushing it. The well people probably quoted you for a 5 or 7gpm pump. That’s why it’s a 1.5hp motor. Do you plan on irrigating?

 

[Runnin4]

There's a hydrophonic green house, pool and a barn that has the 4th bathroom in it.
No irrigation

 

[FredG]

Since you are doing this yourself, buy a grundfos 10S20-27, and a 2hp Franklin motor. This setup has the best chance of lasting the longest.

 

[FredG]

Here is a chart for that pump. It should work well with a 86+ gallon tank, or any size tank with a CSV.

 

[Valveman]

All good advice above. If using a Cycle Stop Valve makes sure the static is at least 300' or there will be more back pressure than the CSV likes with the 10S20-27 pump (195 PSI). But I think you would be fine with the 16S20-18 as long as the pumping level doesn't get below 400'. It would cost less and have much less back pressure (121 PSI).