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not-a-plumber

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I have a drilled 6" well:
Depth 168'
Pipe 128'
Granite rock 40'
Static Level 20'
Recovery rate 20gpm
I won't know where the existing pump is set until I pull it out.
I would like to have everything ready to replace it before removing the existing pump.
I do not know my dynamic level or draw down depth, but with a recovery rate of 20 gpm, and a 10 gpm max pump, I wouldn't think it would be too much.
I'd like to keep the pump in the casing and maybe at 100' depth to make life easy for the new pump.
I will be using a Grundfos 10-SQ7-200 pump.
Is there any reason for me to set the pump any deeper than 100'?
Thanks
 
I wouldn't think the pump needs to be down over 40 feet, if the well recovers 20 gpm and your on;y installing a 10 gpm pump. We have one well that's overflowing 15 gpm now,and never gets much below ground level, I only have the pump down 20 feet in the well, the well is about 60 feet deep.
 
I'm with RS, and your initial impression, you don't need to be down below the worst-case draw-down. That said, putting it deeper isn't harder on the pump, it's only pumping from the dynamic level anyway, no matter how deep it is. Of course, there are secondary effects due to longer pipe and wiring, and the costs of pulling and setting a 160-foot pump versus a 40-foot pump, but you also don't want to find yourself 10 feet short in the dry season. Anywhere between 30 and 60 feet it probably fine, I'd likely do 50 feet just to have more margin.
 
Any setting below 40' is fine unless the water level draws down during a dry year. 100' sounds like a good alternative. It doesn't matter how deep a pump is set as it only lifts from the actual water level. With a static of 40' and a good producing 20 GPM well, your problem is the pump will try to pump about 14 GPM at 50 PSI. If every time you turn on water you use 14 GPM this is not a problem. But in most cases people rarely use the max rate the pump can produce, which causes the pump to cycle on and off constantly. Cycling is the biggest killer of pumps, tanks, pressure switches, check valves, and everything else in your water system. Adding a Cycle Stop Valve to a 10SQ07 makes it deliver strong constant pressure at any flow rate down to as little as 1 GPM. With the CSV you also only need a 4.5 gallon size tank as comes in the PK1A kit. The biggest reason to add a CSV is to make your pump and system last about 4 to 6 times longer than normal.

 
The earth does move and with climate change a reality, you cannot be sure that your static level won't go lower or that your recharge rate won't decrease (I have seen several cases). As wpns noted, the pump is only working against gravity from the static level to the highest faucet. A new pump will likely last 10-20 years (depending on environmental factors such as quality of the water and quality of electric power), so I would put the pump at 100 to 130 ft..
 
Thank you all for your good advice.
I have much more confidence in setting the pump at 100'.

I was going to install a SS check valve directly on top of the pump and I'm sure that it would work fine.
After reading the check valve manufacturer's instructions, most agree that a check valve should not be placed within 5 pipe diameters of another check valve or fitting that changes flow direction, so in my case a minimum of 5" from the pump.
After watching a whole bunch of YouTube videos with conflicting information, I have decided to place one SS check valve 25' above the pump.

Regarding the suggestion to install a constant pressure pump control valve, I did research the Flomatic Cycle Guard valve.
For my application, I have decided against it.
I have a fairly new, very large bladder tank and the pump I have chosen has a integral soft start feature.
My well was drilled in May of 1985 and all evidence points to the pump being the original pump installed by the well driller.
I have owned my house since 2/2001, and I haven't touched it.
Speaking to the previous owners and the close neighbors, no one thinks that it has been replaced.
I'll find out for sure when I pull it, but regardless, it has given great service set up conventionally with a 40-60 pressure switch.
If the bladder tank was old, I might consider a constant pressure pump control valve, but utilizing the existing tank would cause the new pump to run for way too long at the end of each pumping cycle with a flow of only 1 gpm.

Thanks again.
Rather than wait for the pump to fail at an inconvenient time, I plan on picking a nice Saturday and conning my brothers into helping me.
Wish me luck,
Chris
 
I really don't see the need for adding a check valve in the drop pipe, I have never had the one in the top of the pump fail, and putting 2 checks in series might cause them to not seat properly. If the check in the pump were to fail you could always install one at the pressure tank. If the existing pump is hanging on hard pipe you may want to have some scaffolding or tall step ladder to provide a person a place to stand to support the top of each piece of pipe. Good luck with your project and let us know how it went!
 
not-a-plumber said:
Thank you all for your good advice.
I have much more confidence in setting the pump at 100'.

I was going to install a SS check valve directly on top of the pump and I'm sure that it would work fine.
After reading the check valve manufacturer's instructions, most agree that a check valve should not be placed within 5 pipe diameters of another check valve or fitting that changes flow direction, so in my case a minimum of 5" from the pump.
After watching a whole bunch of YouTube videos with conflicting information, I have decided to place one SS check valve 25' above the pump.

Regarding the suggestion to install a constant pressure pump control valve, I did research the Flomatic Cycle Guard valve.
For my application, I have decided against it.
I have a fairly new, very large bladder tank and the pump I have chosen has a integral soft start feature.
My well was drilled in May of 1985 and all evidence points to the pump being the original pump installed by the well driller.
I have owned my house since 2/2001, and I haven't touched it.
Speaking to the previous owners and the close neighbors, no one thinks that it has been replaced.
I'll find out for sure when I pull it, but regardless, it has given great service set up conventionally with a 40-60 pressure switch.
If the bladder tank was old, I might consider a constant pressure pump control valve, but utilizing the existing tank would cause the new pump to run for way too long at the end of each pumping cycle with a flow of only 1 gpm.

Thanks again.
Rather than wait for the pump to fail at an inconvenient time, I plan on picking a nice Saturday and conning my brothers into helping me.
Wish me luck,
Chris
Click to expand...

Lol! Watching a bunch of Youtube videos will confuse anybody. Youtube thrives on disinformation. They get six times more clicks from fake news than from real news, so they encourage videos with bad advice. There is a guy who has made hours of inaccurate videos about Cycle Stop Valves and even mentions Flomatic Cycle Guard. Youtube will do nothing about it as the guy says it is all his opinions. It doesn't matter that opinions have no place in a subject where so many facts are available. I have plenty of facts, with charts, curves, and literature to prove what I am saying. Yet thousands of people see his wildly inaccurate videos and thinks there is some truth to them when there is not. All the bad information on the Internet is the reason I started working on forums 10-15 years ago, to help people get some facts. Like the crazy guy I mention, making your own assumptions from idiotic opinions on Youtube is not a good way to design a pump system. You should get your advice from someone with over 50 years experience with drilling and pumps that guarantees everything he does and or sells. :)

Just like I am right about the fittings being galvanized, not Stainless Steel, I am right about everything else as well and old enough to not put up with the idiots on or at Youtube. And I guarantee it!!

First, the spring-less check valve in the SQ pump are some of the best you can get. I have installed many thousands of Grundfos pumps and never added an extra check valve to the system. The check valve in the pump also works better when it is the only check in the system, as there is more pressure to hold it closed.

Second, "manufacturers instructions" about 5 pipe diameters or adding additional check valves every 100' is such bad advice you can also find that on Youtube. Manufacturers are out to make money and they will not tell you the best way to install and control a pump or they would recommend a CSV on everyone. Recommending a CSV on every pump would eliminate the replacement pump business completely, which is why they don't recommend a CSV.

Third, you are listening to idiots on Youtube to come up with that info about a CSV taking too long to fill a large tank. If they don't understand something that simple is not true, they don't understand anything else either. When using a large pressure tank the CSV is set at 58 PSI while using a 40/60 pressure switch. This makes the large tank fill in the same 2-3 minutes, and maybe one minute more than without the CSV, which is a good thing.

Forth. yes Flomatic has a copy of every Cycle Stop Valve I make. It is flattering and additional proof that the CSV is the best thing for pumps.

Fifth, the soft start feature in the SQ pump is fine, but mostly another sales gimmick. The only time a soft start feature would help is if your pump is cycling on and off too much anyway. Adding a Cycle Stop Valve solves the root problem, which is cycling, and gives a mechanical soft start and stop feature that is better than the electronic type.

Lastly, even the bladder in your large tank will last longer, just like the pump, when a Cycle Stop Valve is added.

You came here for advice. You should consider the source and trust someone who guarantees his work and can be reached by phone if you have any questions. Designing a system from "opinions" on Youtube is the best way to end up on Youtube showing all the problems you are having.
 
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Like Valveman said, you need to consider the source of your information. YouTube is pretty good at getting information on car repair when you can see the mechanic perform the repair step by step. But when you see that after slapping a watermelon on both ends your watermelon will be "pealed" when you cut it open, perhaps everything on YouTube isn't really the truth.

Consider YouTube that accepts any and all videos, versus a forum where professionals share their wisdom which has administrators and other professionals monitoring the information provided. Now which one would I put my trust in?
 
Like me, there are others who try to put accurate technical videos on Youtube. However, they get lost in all the opinions from someone who's brother in law has a buddy that used to have a well pump. There are even some engineers with such inflated ego's they think they know everything and won't listen to facts that would prove their inadequacies. Just like someone in a cult that would never admit they are in a cult, or someone with a mental illness that doesn't know he has a problem, stupid people don't know they are stupid. They just keep posting videos on Youtube and proving they are stupid to those of us who know the facts or at least can see through their BS.
 
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