I have a vacation cabin that has a shallow well pump in a 8' deep covered pit. The well is 1 1/4" pipe and water quality is excellent. The pump is very old and noisey and can't quite hit the 40psi cut-out of the pressure switch so I had to reduce the setting to 35psi last weekend (when I opened the cabin). I'm a new owner so I don't know the well history other than it appears to be hand-driven as the driver is still down in the pit

I'd rather replace the nasty old mess in the pit with new. I got lucky and found a horizontal bladder tank with attached pump platform on clearance but the pumps in the big box stores didn't impress me. How do I choose how many HP to buy? Obviously I want the best pressure & flow I can get...but without sucking my well dry.

 

If the flow from the old pump is working for you, then get a new pump of the same size.

 

I'd like more. How does a well guy determine what size pump to install?

 

I would say that to determine how much water your well will produce, you could rent a portable "mud pump" and pump it out to see what the recovery rate is.
However, if is just a vacation cabin, around 4 or 5 GPM would be plenty of water.
I run my house on about 5 GPM no problem.
I have a Ace hardware 1/2 hp shallow well pump ($149.) that is rated for about 10 gpm, I would highly recommend it to you, as I have had good service from it.

 

Looks good. Any idea who makes it for Ace? It looks a little different from Wayne, Gould, WellSaver...
What's the cut in/out pressure of the built-in switch?

 

I believe it is made by Meyers Pumps.
It comes with a 30/50 pressure switch.
You may be able to find one with a 40/60.

 

Unless you test the well for flow first, I would replace the old pump with 1/2 hp and no more than a 3/4 hp. The pressure switch is usually set at 20/40 but you can increase that by turning the long screw on the pressure switch clockwise (each turn will increase the pressure about 1-1/2 lbs.) For a cabin I recommend using a small 102 Well-X-Trol tank (or equivalent) and a Cycle Stop Valve www.cyclestopvalves.com CSV-140. Installing this will give you a constant pressure and prevent the pump from cycling. This valve can be purchased from any well supplier for about $100.00 or less or you can order it from www.pumpsandwells.com. Keep in mind the pressure in the tank must be 2 lbs less than the cut on pressure. The CSV-140 will give you 40 lbs of constant pressure. You'll love it!

 

Hi,

I would like to add a little input here. Meyers Pumps are pretty good pumps. I personally am a Goulds fan. Appear to be the best pump in my area, and I think a 1/2hp should be fine for you.

Don' forget you will need to make sure it is a one pipe pump because some jet pumps can be either shallow or deep well pumps. Depending on where the jet assembly is installed,
(either on the pump(shallow well) or in the well (deep well), determines which pump you need. So basically make sure you specifically ask for a shallow well pump or make sure it has a Shallow well adapter either installed on the pump or sold with it. I hope I didn't confuse you on this. If I did, let me know.

A 30/50 pressure switch is pretty common now. Used to see more 20/40 switches. You can change it to a 40/60 later if you want and with a 30/50 there is a way to increase it. Some pumps might have a hard time with the higher pressures, but a 1/2hp with only 8' of lift should be fine.

 

I struck out at ACE so I bought a Goulds from a trusted plumbing supply nearby. The 1/2HP J5S is a heavy beast of a pump! I'm in the process of gathering all the pipe & fittings to assemble the pump & tank before taking it up north. Hope to make this a painless swap while improving everything along the way.

 

Good luck guy48065,

If you get stuck you know where to find us.

 

Thanks!

I'm still unsure if I should measure the water depth in my well or leave well enough (LOL) alone.