Choosing a well pump and motor

[SueInVA]

I’ve got a well that was drilled 6 years ago but never had a pump installed. My building contractor is going to have the pump installed and run to the house but I’ve got to buy the pump. After being ghosted by the guy who drilled the original well, I’ve been reading and watching all the well pump videos that I can find to educate myself. When I found this forum, I did a happy dance. I’m looking for a pump that will last and will provide plenty of water. Here’s what I have:

Total Well Depth: 260'
Depth to bedrock: 47’
Granite: 47-245’
Water zone: 245-250’
Granite: 250-260'
6” PVC: 70
Natural Flow rate: 50 GPM
Use: 5.5 bath, kitchen, laundry, kitchenette

I found one that’s new but has been in the warehouse "awhile".

4" Grundfos submersible Well Pump 45S15-4, motor: MS402 1.5HP 3/60/460V 3 Cond + Grd , 47 GPM, 3450 rpm

Is this a good option or are there better choices? Does sitting in a warehouse a couple years affect anything? At what depth would you put the pump? Is it better to pick the pump then the motor, the motor then the pump, or a packaged set?

Any and all feedback greatly appreciated.

-Sue in Virginia

 

[Valveman]

You didn't say how deep it is to the static water level, which is important. But I am guessing from the other stuff you mentioned that the water level is fairly high, like above 100'? If that is the case I would set a 10 GPM, 1HP at maybe 220' deep and use a PK1A kit with a 10 gallon size pressure tank. That pump will give you as much pressure as you want. I would try setting the CSV to deliver 60 PSI constant and use it with a 50/70 pressure switch. If you want more pressure, you can turn it up. But with 60 PSI constant most people say they don't even need soap in the shower.

There is a reason that pump you mentioned hasn't been used. It will pump enough water for 6-8 houses, but can't build more than 50 PSI pressure even if it was pumping from a cistern tank. It is too high volume and low pressure to work as a normal house well pump. And the motor is 480V three phase, which won't work on power from a house.

 

[JEG in Raleigh]

You didn't say how deep it is to the static water level, which is important. But I am guessing from the other stuff you mentioned that the water level is fairly high, like above 100'? If that is the case I would set a 10 GPM, 1HP at maybe 220' deep and use a PK1A kit with a 10 gallon size pressure tank. That pump will give you as much pressure as you want. I would try setting the CSV to deliver 60 PSI constant and use it with a 50/70 pressure switch. If you want more pressure, you can turn it up. But with 60 PSI constant most people say they don't even need soap in the shower.

There is a reason that pump you mentioned hasn't been used. It will pump enough water for 6-8 houses, but can't build more than 50 PSI pressure even if it was pumping from a cistern tank. It is too high volume and low pressure to work as a normal house well pump. And the motor is 480V three phase, which won't work on power from a house.

Valveman, my well is also 6" in diameter and you helped me several years ago after my new pump, also a 1.5 hp Grundfos, burned up in 2 weeks because it was much too high volume. It was replaced with a 1 hp 10 GPM pump that has worked great with no problems. At that time, you also advised me to put a cooling shroud around the new 1 hp pump because the borehole was 2" larger than the diameter of the 4" diameter pump and without the shroud, the pump could burn up because it did not get adequate cooling (the 1.5 hp pump that burned up did not have a cooling shroud). I did make and install a cooling shroud out of PVC pipe on the 1 hp pump and as I said, I have had no problems. I also have a CSV on the system.

 

[SueInVA]

Thanks for the replies.

Valveman, my static water level is 55'.

JEG, which pump/motor did you end up installing?

 

[Valveman]

With a static of 55' you could use a 10 GPM, 3/4HP and set it about 200' deep. Grundfos model number would be 10S07-12. Goulds is 10GS07. But I am not sure the name brands are worth the difference these days. Some of my customers say they are having good luck with the Tuhorse brand pump. That size pump is a commodity for many outlets. The County Line at TC seems to be fine. Even Utilitech and Flotec are ok as long as they have plastic end bells and not the cast iron ones.

Oh yeah, a Shroud is always a good idea.

 

[JEG in Raleigh]

Thanks for the replies.

Valveman, my static water level is 55'.

JEG, which pump/motor did you end up installing?t

The particular pump I have is a Grundfos 10S10-15. This is a 1 hp, 230 volts, 2 wire (as opposed to 3 wire), 10 GPM pump. But my well is also 800' deep. My static water level is at 30'. Valveman is one of the experts on this site regarding wells, and I would listen to his recommendations. Attached is a photo of the shroud I made before putting it on the pump.

 

[SueInVA]

Watching more videos to understand how CSV works. The more I learn, the more questions I have. Thanks for your patience.

1. 10 GPM seems low for the number of potential water “events" I could have at one time (5.5 baths, 2 kitchens, laundry, 2 spigots). How do I know that’s enough GPM?

2. I watched a video before that made me think a 3 wire plumb was better than a 2 wire pump. Pros/cons?

3. Looks like you pick the psi for the valve when you buy it (not changeable). Why would you choose anything less than 60 psi (assuming more water pressure is better than less but don’t want to damage plumbing fixtures)?

4. How do I know voltage is correct (no power run to well yet)?

5. Will have two tankless hot water heaters. Does that affect system design?

6. If down the road we add a water softener, does that affect the system?

Thanks again!

 

[Valveman]

Rarely does even a large house use more than 5 GPM. A 10 GPM pump will run 3 or 4 showers at the same time, but not 5. One of the many benefits of the CSV is that it allows you to use as large a pump as you think you need, and the CSV will make it work like a small pump when only 1 shower is needed at a time. That same PK1A kit will work with a pump up to 25 GPM. You can use a 2HP like a 25GS20 Goulds or a 25S20 Grundfos, which will give you up to 25 GPM, and the CSV will make it work all the way down to 1 GPM when needed.

3 wire motors with a control box are preferable for several reasons. You have a choice of 2 or 3 wire on the smaller motors, but 2HP only comes in 3 wire and needs the control box.

The CSV125 valves are not adjustable and come in 40. 50 , or 60 PSI. But the CSV1A as comes in the PK1A kit is adjustable from 15 to 150 PSI.....

Any pump larger than 1/2HP will need 240V single phase, which is standard house current.

Tankless water heaters work better with a Cycle Stop Valve. With the old 40/60 or 50/70 pressure switch the instant heaters will turn on and off while a shower is going as the flow varies widely and the pressure goes up and down from 50 to 70 over and over. With the CSV the shower pressure stays strong and constant 60 PSI, which keeps flow through the instant heater stable and they stay on as needed.

A softener or filter of any kind is an extra loss of pressure. Starting with 60 PSI constant and a 50/70 switch means you should get 50 PSI constant on the outlet side of a softener or filter. The more losses you have in the softener of filter, the higher you want the CSV set pressure.

 

[Twowaxhack]

A tub filler can easily use 5-10 gpm by itself.

So if you have a large tub, size accordingly.

Washing machines are also a high flow appliance.

 

[JEG in Raleigh]

Watching more videos to understand how CSV works. The more I learn, the more questions I have. Thanks for your patience.

1. 10 GPM seems low for the number of potential water “events" I could have at one time (5.5 baths, 2 kitchens, laundry, 2 spigots). How do I know that’s enough GPM?

2. I watched a video before that made me think a 3 wire plumb was better than a 2 wire pump. Pros/cons?

3. Looks like you pick the psi for the valve when you buy it (not changeable). Why would you choose anything less than 60 psi (assuming more water pressure is better than less but don’t want to damage plumbing fixtures)?

4. How do I know voltage is correct (no power run to well yet)?

5. Will have two tankless hot water heaters. Does that affect system design?

6. If down the road we add a water softener, does that affect the system?

Thanks again!

This link gives a good short summary of the plusses and minuses of 2-wire vs. 3-wire pumps.

https://www.waterpumpsdirect.com/st...tting into too much,than 1.5 HP (horsepower).