Deep well pump with long run to storage tank

[Charliekaiser]

Hi folks. Looking for some advice. First, as a caveat; I am NOT a plumber or well expert. But I know enough to be dangerous... ;-)
We have a new well that's about 200 ft deep. It's located about 650 ft from our 2500 gallon storage tank, which is currently plumbed and pressure-tanked into our house. (No direct pressure from pump to house plumbing)The elevation change from the wellhead to the tank is negligible. Well test showed >35gpm available at the wellhead.
Power for the pump will come from the same location as the storage tank, so a significant wire run.
Our well contractor is proposing a Goulds 13GS07 installation. He says it should produce 15gpm, but looking at the spec sheet, I see that a 200' head on that pump rates it at 8 gpm. He's also proposing 1 1/4" pipe back to the tank. Wiring is proposed as #8 thhn.
My concerns... one, it looks like that pump won't be powerful enough to provide 15gpm back to the tank. In fact, it looks like that pump will barely handle the depth of that well, looking at the performance charts.
Two, with the length of the pipe run, I'm concerned that 1 1/4" pipe might provide too much restriction and overwork the pump. I know the pump is a 1 1/4" outlet, but 650 ft is a loooong run.
Third, my limited research shows that thhn is not rated for direct burial, but I don't see any mention of conduit in the estimate.
Fourth, 850 ft (depth plus run) seems like a long way for #8 wire.

So... Should I be asking for a larger capacity pump? Seems like this one will need to work too hard. I'd rather pay more up front and not have to repair/replace this thing in 5 years. If so, any model/size recommendations?
Also, will maybe 1 1/2" pipe back to the tank help with flow or not?
Should I ask for direct burial cable or at least verify conduit will be used?
And should I be looking at thicker wire?

Oh; I'm also considering a "tap" about halfway along the yard run to provide water to an outdoor water feature. any problems with that?

And one more touchy question... He's pricing the pump at $1170 but I'm seeing it online for about 60% of that. I'm considering suggesting that I provide the pump to save a chunk of cash, but I know there is some markup profit involved and don't want to tick him off... Any thoughts?

Thanks.

Charlie
Kingman, AZ

 

[Valveman]

My first question is why would you want a cistern and extra booster pump when your well makes 35 GPM? Just put in a well pump that will do the flow and pressure you need, and use the pressure tank for the well pump. Then you can tap into that line anywhere you want, you won't be having to double pump the same water, and the water will be fresh and clean coming straight from the well, unlike being exposed to air and sitting in a cistern tank long enough to get stale and/or contaminated, and needing chlorine to be safe.

Cisterns are used when the well only makes 1-2 GPM, and you need the cistern to store enough water to use as needed in the house. I would never use a cistern if the well can supply sufficient volume.

They make direct burial cable out of THHN, and it works very well. And there are wire size charts for which ever size pump you end up installing.

That sounds like the typicle markup a pump installers wants and needs. But if he is designing this system with the cistern, I would be suspicious of anything he does.

 

[Sponsor]

 

[Reach4]

How far down is your water? From the table below, if your water level is 160 ft below your cistern, that pump is expected to pump 15 GPM. To fill cistern, you would use the 0 PSI row.

Valveman is right. Why have the cistern in the system? If it is a supply for the fire department to be able to dip into, you could just fill a tank for that purpose.

And one more touchy question... He's pricing the pump at $1170 but I'm seeing it online for about 60% of that. I'm considering suggesting that I provide the pump to save a chunk of cash, but I know there is some markup profit involved and don't want to tick him off... Any thoughts?

The markup on the pump is a big profit item. Some well people charge 100 % markup or so. Plus, if the pump he puts in does not work initially, I expect he would eat the labor to get a replacement and put it down there. If the pump that you order is DOA, I am confident that you pay for the re-do. What I don't know is if the pump he sells fails after 1 month or 8 months, what do you get charged for installing the warranty replacement? Yep. Sensitive subject.

 

[Charliekaiser]

Storage tank is already in place with the existing (200 gp DAY) well. Plus, wells here in northern AZ can be, shall we say, less than reliable, especially in the hot summer months... ;-)

 

[Reach4]

Storage tank is already in place with the existing (200 gp DAY) well. Plus, wells here in northern AZ can be, shall we say, less than reliable, especially in the hot summer months... ;-)

Why would you want a 13 or 15 GPM pump then? A 10GS05 would seem to be a better choice for such a well.

 

[ThirdGenPump]

Just to echo the others if you are pumping into a cistern tank what does the flow of the pump matter? Do you use more than 2500 gallons at a time? Pumping rate doesn't much matter if it has 24 hours to fill it. Throw in a 1/2 HP then you can use #10 wire and 1 inch pipe to minimize your cost.

I'd bypass he cistern, in which case you do need to worry about flow and friction loss so the pump and pipe size will make a difference. The amount of lift the pump has to make is a major determining factor. Reach4 showed you the chart for that pump.

#8 wire is fine for a 3/4 HP at that distance. It would also cover a 1hp(max on a goulds 1HP is 908ft of #8 on a 3 wire motor, you can stretch further with 2 wire motors.

Fiction loss for 800ft of 1 1/4 at 15gpm is about 10psi the pump can make up that loss no problem. 1 1/2 would lose about 2.5psi. not worth the upgrade in my opinion it's a sizable price bump.

Your missing the motor in your model number. Pumps in that size are typically sold with the motor paired. A for a 13gpm with a 3/4 3 wire motor it is a 13GS07412 Goulds MSRP including the control box is listed at $1077. Your pump guy pays wholesale and charges MSRP, which is completely reasonable. They have to cover costs like the time they spent providing that free proposal, you wouldn't even know what to ask without it.

If you buy a Gould's pump online Goulds does not honor the warranty. If it's sold and installed by a certified Gould's installer it carries a 5 year manufacturers warranty. My company will not install a customer provided pump, it's not worth the hassle if something doesn't work. If I sold and installed it and it breaks within a year it's entirely our problem.

 

[Charliekaiser]

wow... that's a bunch of good info, guys. Thanks. I really appreciate it. As mentioned, I know enough to be dangerous. LOL... I'm meeting with the contractor Monday. I feel much better about what he's proposing.

Thanks again!
Charlie
Kingman, AZ