Some well pump questions

Hello everyone.

I have a well that's 720' deep. The pump is set at 400'. (I know. That's pretty deep). The water table is about 20 feet down. The well is rated at 6 gpm. The pump and tank were installed eight years ago.

How long can I expect it to last? (I know - a lot of variables). We use it sparingly. No watering of grass. Up till five years ago it was just me and my wife. Now we have two little boys.

Our water has high ph - around 9.6. Would that have any affect on the pump?

The pump is a Gould's. The paperwork says it's a model 7GS05 but it the sticker for the motor says it's a Franklin mod. 2445089003 1hp. The Franklin site does not list that motor/pump combo. I suspect it's a 7GS10. The guy who installed it was having conflicts with his bosses widow and didn't come across as too bright.

In any case I am interested in some preventative maintenance. I would like to replace the pump/motor before it goes bad and would really like to do it myself - with help.

I checked the pump and it's drawing about 10.2 Amps. It's rated at 8.2. I checked without the water running so it was pressurizing the tank.

I have 3.5 ohms across the motor and about 5 meg ohms to ground.

Also, is it true that the the pump is really only pumping about a fifty foot head (from water level to top floor of the house)?

I know it's a tough job to change the pump. I lost my job (industrial electrician) and am out of work right now.

Can someone tell me the way to make the t-bar to lift the pump out with? I remember it was made out of 1" pipe and can't remember the fitting on the end.

Thanks in advance,

Ray

Just a 1" pipe with either male or female threads on the bottom end and a pipe wrench is all you need to get started pulling. Use a flashlight or a mirror on a sunny day to see what's down the hole for threads.

Get some help, it's going to be a bit heavy and if you have minerals in your water which practically everyone has, that pipe is going to get a bit slippery.

You can shop for a new Submersible Pump here.

bob...

Can anyone answer more of my questions? Please.

If the well's 720' deep the pump should be set at 700' that way you have a huge reserve of water in the well case.

To get the total head add 2.31 ft per psi of pressure in the tank. At 40 and 60 psi you add 92 ft and 138 ft. Add that to the difference in elevation between water in the well and the level of the tank. Total head is probably in the range of 120 to 160 ft.

The resistance for the main winding of a 1/2 HP motor is 4.2 Ohms, and 2.2 Ohms for a 1 HP motor. http://www.goulds.com/pdf/IM096.pdf

If the 3.5 Ohm measurement includes the wire then you probably have a 1 HP motor. Resistance of 800 ft of #12 would be about 1.4 Ohms.

Putting a larger motor on a pump doesn't change the characteristics of the pump. A 7GS05 pump with a 1 HP motor has the characteristics of a 7GS05 pump.

I doubt that your pump is a real 7GS10. If it is a real 7GS10 then you are operating far beyond the curve (12 to 14 GPM) and could be mechanically overloading the pump.

The current of 10 Amps is a little high but the pump is operating past its recommended curve (more GPM) which will increased the current. http://www.goulds.com/pdf/7310.pdf

The problem with operating a well over a very large range of drawdown to use all of the water in the bore is that it forces the pump to operate over a very large range of head. If the pump is sized to operate when the water is low in the well, then when the water level is high there is very little head against the pump. The resulting high flow overloads the mechanical parts of the pump as it operates beyond the end of the rating curve. That problem can be solved by putting a flow-limiting valve (A Dole Valve) in the line before the tank to limit the flow of the pump to the maximum rating. For example, the 7GS pump series has a recommended limit of 10 GPM so you could install a 7GS10 with a flow control valve to operate over a greater range of depth.

On the other hand, if you are getting adequate water with your system then there is no need to increase the pump and the 7GS05 will do all you need.

Thanks for the replies.

I will read and think about them.

Leave it alone!

If the system is working OK leave it alone! If you want to ad life to your pump; tank; pressure switch and if you like constant pressure (like city water pressure) look into a Cycle Stop Valve www.cyclestopvalves.com. A CSV will cost you less than $100.00, is simple to install and you will be amazed!

Try it, I promise you'll like it.

Ray

Ray, My personal waterwells have Franklin 1 hp motor operated pumps and have been untouched for over 20 yrs. Somedays I use as much as 1000 gallons due to watering livestock. That's on a tank with maybe 6 gallons drawdown and a standard pressure switch. If the high PH is not hard on pumps then you should be good for a number of years. Around here there are still a few Reda brand pumps being pulled up and they been out of business forever.