Well pump sizing

[IXLR8]

Hi folks,
The 40 year old well pump in our house in NC is getting flaky and it is time to replace it. The pump is in a pump house, it is a 1hp vertical pump. The well is about 100 ft deep and about 100 ft from pump to the house, don't know how deep the water table is. A replacement vertical 1hp pump is around $1000.00!!! Do I really need a 1hp pump? Can I just build a stand for a horizontal pump and do a little re-plumbing and get a cheaper pump? Any input would be appreciated.

 

[MAX-24-Dean]

Hi folks,
The 40 year old well pump in our house in NC is getting flaky and it is time to replace it. The pump is in a pump house, it is a 1hp vertical pump. The well is about 100 ft deep and about 100 ft from pump to the house, don't know how deep the water table is. A replacement vertical 1hp pump is around $1000.00!!! Do I really need a 1hp pump? Can I just build a stand for a horizontal pump and do a little re-plumbing and get a cheaper pump? Any input would be appreciated.

A "horizontal pump" (centrifugal pump) only has a lift capacity of about 25 feet. If your well is only 100 feet deep you would only need a 1/2 HP (vertical pump) motor unless you irrigate a garden out of this well and want more gpm.

 

[tradosaurus]

Hi folks,
The 40 year old well pump in our house in NC is getting flaky and it is time to replace it. The pump is in a pump house, it is a 1hp vertical pump. The well is about 100 ft deep and about 100 ft from pump to the house, don't know how deep the water table is. A replacement vertical 1hp pump is around $1000.00!!! Do I really need a 1hp pump? Can I just build a stand for a horizontal pump and do a little re-plumbing and get a cheaper pump? Any input would be appreciated.

I replaced my 1 HP convertible jet pump with a 1/2 hp 10 gpm submersible pump. Granted mine is a 42 ft shallow well and pipes water about the same distance (100 ft) to the house.

Quieter operation and used less power. Couldn't stand how loud the jet pump was since it was located above the well and the well is located in the shed where my tools are located.

 

[ning]

Definitely need to know how deep the pump is in the well, as well as whether or not the house is higher than the well. At most you'll need a 3/4hp, likely 1/2hp. This depends on desired flow rate and total head, which is the height difference from the pump to the high point in the house (multistory houses need slightly higher pressure).

My well is 180' deep, pump is at 165', bottom floor of house is 15' above the well, two-story house, about 150' pipe between the well house and the house with some 45* bends... all these things contribute to "needs more pump". 3/4hp gives me 10gpm, which is more than the well can handle for very long (but is fine for relatively short uses, like filling a tub) (well the total depth of the well doesn't matter for this but for other things).

 

[Sportsman762]

The depth of a well is irrelevant, I worked on a 300' well that had a pump hung at 27', it was an odd area where the water was deep, but the water level was high. How deep is the water table, how much draw down does the well have, what is the desired flow rate (or the production capacity of the well), and how far must it pump. A low production well, will draw down bad when pumped so the pump has to be hung deeper.
I am guessing a "vertical pump" is located in the well on the bottom of the drop pipe? If so this is considered a submersible pump as it is submerged. I am guessing a "horizontal pump" would be a jet pump like tradosaurus's photo shows. If your going from a jet pump to a submersible pump, you will need more pipe as you have two pipes going down the well, and you will need a venturi / foot valve on the bottom. Jet pumps pump some water down the well, through the venturi that creates suction, bringing up more water than you pumped down. A damn inefficient way to move water.

If the pump is hung at 100', you are going to need a submersible pump as jet pumps are good for shallow wells.

I would not go with a jet pump over a submersible. They are much less efficient, and it would be a pain to switch from a submersible to a jet, your cost savings would also be eaten up when you factor in the additional pipe, venturi, and pump. I would just switch the pump out, as long as it has worked well in the past.

 

[gary49]

I’m not sure what you mean by vertical pump that is in a pump house. That implies that the pump is above the ground and as others have noted, a shallow well jet pump is the type of pump one typically sees above ground. I believe I’ve seen illustrations of a jet pump that uses the well pipe to carry water up, maybe the well is one of those? If so, I think the casing of the well would be 2” nominal pipe. There are deep well jet pumps, and they use two pipes down the well, with an ejector assembly at the bottom above a foot valve (check valve with a screen). I think you will want a submersible pump, on a 100’ well it would typically be 85-90’ down. Jet pump is less efficient and more troublesome than a submersible. Is your well too small for a submersible pump? Hopefully it is a 6” well, but it could be smaller which might explain why it has what sounds like some form of jet pump. 1/2 hp should be fine on a 100’ well assuming you don’t have a need for water flow beyond 10 gpm and assuming you can install a submersible pump.

 

[IXLR8]

The pump is sitting on top of a piece of 1-1/4" PVC about 12" above the ground. It is a level run to the house, maybe up 2 ft. There is that single pipe going down into the well that the pump sits on and one pipe heading to the house.

 

[ning]

The pump is sitting on top of a piece of 1-1/4" PVC about 12" above the ground. It is a level run to the house, maybe up 2 ft. There is that single pipe going down into the well that the pump sits on and one pipe heading to the house.

Can you show a pic of the pump?

 

[caver]

I was doing homework for a well I will have drilled possibly this summer on my home build site. This young guy gives lots of advice and seems pretty solid. He seems to focus on the service call and fracking side but the family? business also drills wells. https://www.youtube.com/@h2omechanic

 

[3Ts]

I have seen vertical pumps that sit over the well, BUT they have all been agricultural wells, meaning they're about a foot in diameter and pump hundreds of gallons per minute. So, I'm confused as to what you actually have. All the above ground pumps I'm aware of can not lift water more than 25 feet.

The distance in elevation from the water surface in the well to the house will determine the pump specifications. The flow rate and size of pipe will add a little to it.

 

[camshawn]

You need to know how high the pump will lift water and the flow you need. The pump needs to be sized for both. You compare these numbers to the pump cure to make sure the head/ flow is within the HP rating of the pump selected or the motor will fail. A water well/ pump shop will pull the HP you need from their head based on experience. The other way to size the pump is to guess what you need and look up the pump curve on the internet. Cam

 

[jyoutz]

My 680’ well has a 5” casing, and is 400’ from the house. You don’t even want to think about what the 2hp submersible pump cost to replace. $1000 doesn’t seem too bad since you have received decades of good service from your current pump.

 

[mikester]

Hi folks,
The 40 year old well pump in our house in NC is getting flaky and it is time to replace it. The pump is in a pump house, it is a 1hp vertical pump. The well is about 100 ft deep and about 100 ft from pump to the house, don't know how deep the water table is. A replacement vertical 1hp pump is around $1000.00!!! Do I really need a 1hp pump? Can I just build a stand for a horizontal pump and do a little re-plumbing and get a cheaper pump? Any input would be appreciated.

$10

 

[Valveman]

The pump is sitting on top of a piece of 1-1/4" PVC about 12" above the ground. It is a level run to the house, maybe up 2 ft. There is that single pipe going down into the well that the pump sits on and one pipe heading to the house.

Sounds like a deep well jet pump. Like was said switching to a submersible can have many advantages. But I am afraid you may have only 2.5" casing. The casing will need to be at least 4" diameter to use a submersible. If it is 2" or 2.5" casing you are stuck with an ejector at the bottom and a vertical deep well jet pump up top.

 

[Egon]

Pictures of different surface pump set ups.

 

[Valveman]

I think yours may have the motor on top like a vertical jet pump.

 

[IXLR8]

Here are a few pics of the pump. You might be correct Valveman.

 

[Valveman]

Yep. Looks like 2" casing which means you are stuck replacing the with same kind of pump. Those are good pumps though and work well with a Cycle Stop Valve.

 

[ning]

Next question, then: what do you mean by "flaky"?
Does it work sometimes, not others? Or is it just not building as much pressure?

It's possible a rebuild may be sufficient.
Regardless, there's probably a lot less effort since it's sitting on top and you don't have to pull something out of the ground.

 

[IXLR8]

"Flaky" translated:
About 6 months ago the well pressure tank lost all it's air and the pump was short cycling. I put air in the tank, after replacing a dried up Schroeder valve, which stopped the short cycling, but it didn't sound good. Fast forward to Tuesday afternoon and there was no water in the house and the pump motor was HOT, like couldn't touch it hot. Miss's is at the house in NC, I'm at our home in VA. I had her turn the breaker off for the pump and check the pressure switch. That looked good. I had her check a few other things and then turn the breaker back on. When she turned on the breaker... the motor made a humming noise but nothing happened. Motor didn't turn. I told her to shut off the breaker. She called a plumber who came out the next day while she was at a doctors appt. When she got home from the appt., she had water!!?? She called the plumber and he said he pulled something apart and cleaned it up and it is working. He said it might work for 4 hours, or it might work for another 40 years. Since this does not look to be a 'normal' pump we were trying to be proactive and find a replacement. According to the label, the pump is an AOSmith unit. I can't find anything online that even looks like it.