Author Topic: Just got a new larger well pump and want to keep it healthy  (Read 142 times)

JEG in Raleigh

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I'm not dealing with irrigation well issues....just the well for my house.  I have an 800' deep well (water level 30' below the top of the casing) and had been having problems with the 4-year old 3/4 hp well pump, 8 gph, supplying my domestic water.  It had been set at 300' and never provided enough volume if more than one valve was open.  The check valve wasn't working either. I have a Well-X Trol 44 gallon pressure tank.  I told the pump installer that I wanted more volume and pressure, and a high quality pump.  They put in a 1.5 hp Gurundfos producing 10 ghp, and set it at 500'.  Well, I'm an idiot, and did not look at what gauge wire was feeding the old pump, and it was only 14/2 (well is 120' from my breaker panel).  So, when they installed the new well pump, they ran 8/2 wire down the well and connected that to the 14/2 wire coming out of the panel.  The day after the installation, I was running an outdoor hose for 20-25 minutes and I suddenly lose water pressure.  I fumbled around flipping the breaker (that didn't work) and was scratching my head for 5 minutes, when the pump came back on.  The manual said the pump had a thermal overload safety and at that point I checked the breaker size and wire size against what the manual said and discovered the undersized wire and breaker.  So, I'm having an electrician run a subpanel out to the well with 8/2 wire and I want to make sure I'm doing everything I can to extend the life of the pump. 

That brings me to the CSV.  So now with the more powerful pump being 200' deeper in the well, with 470' of head, someone on another forum suggested I might have a worry with upthrust, and suggested I might need a larger pressure tank, I'm guessing because the more powerful pump will now cycle on and quickly fill the pressure tank, then cycle off too quickly.  So, I am trying to figure out the best way to minimize the potential issue with upthrust and reduce the cycling on and off of the pump.  I don't have room for a larger pressure tank, but I can add a second pressure tank in the closet behind my utility room where the current pressure tank is. 

QUESTIONS: 
1.  I'm not clear about this.....can I use the CSV with a pressure tank? 
2.  Will the pressure tank fill up when the CSV is managing a minimal flow, like a single sink valve running or must the CSV not be restricting flow for the pressure tank to fill?
3.  If I turn on a bathtub valve to fill a bathtub, and that drains my pressure tank after a number of minutes, and the CSV kicks in and regulates the flow and then I turn off the tub valve and stop all water flow, will the pressure tank fill up again?
4.  Will a CSV have any positive effect on minimizing upthrust?

I'm a total rookie here, so answers and explanations like you'd give to a 2nd grader would be helpful.  Thanks.

Cary Austin

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Re: Just got a new larger well pump and want to keep it healthy
« Reply #1 on: July 06, 2019, 04:05:46 PM »
I don't think the #14 wire will cause the overload to trip.  You can actually run a 1.5HP on #14 wire as long as 190'.  It will work like a reduced voltage soft starter and should not trip the overload.  If it did trip the overload, it would be on start up.  Since the pump was running when it tripped the overload, I am guessing it is a flow issue and the motor is not getting cooling. If the pump is set below where the water comes into the well, it is top feeding the pump, and the motor will get hot.  Do you know if the well is cased, or where the water is coming into the well?

Upthrust will be a problem.  It doesn't matter that the pump is set at 500', it is still only lifting from the water level of 30'.  So you have a pump designed for 500' with only 145' of head on it.  The only time it will see 470' of head is when the water level has been pulled down to 370'.  Having such a deep set pump is such a shallow well means there will be 230 PSI on the CSV and the pipe before the CSV.

Yes a CSV helps with upthrust.  But you have gotten such an over sized pump it will take two CSV1A valve to bring it down from 230 PSI to 50 PSI.  And yes a CSV works with a pressure tank. 

Explanation for a second grader is to find out why it is tripping the overload, because the #14 wire isn't the problem.  I am thinking the pump is set too deep to get cooling from below the motor.

Also see our video as to how a CSV works here.
https://vimeo.com/248374194

JEG in Raleigh

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Re: Just got a new larger well pump and want to keep it healthy
« Reply #2 on: July 06, 2019, 08:02:30 PM »
Cary, thanks for your reply.  I don't understand what you are saying in your comment about upthrust.....I don't understand the math. I have an 8" well casing for my house.  The well had recently been bored when we purchased the property.  A developer was going to try to develop it into 10 building lots, and they bored the well intending for it to be a community well.  It did not produce enough water for that, but according to the well report, the well is 815' deep and the 8" well casing depth is 63'. 

Other notes on the well report: 
1.  WATER LEVEL BELOW TOP OF CASING = 33'
2.  WATER ZONES (depth) from 645' to 646' and from 740' to 741' (I don't know what this means)
3.  YIELD - 10 GPM

Back to my not understanding what you are saying about upthrust;  the water level below the top of the casing is 33' and the well pump is at 500' from the top of the casing.  Doesn't that mean the head is 500'-33'=467'?  Could you please explain or point me to a link that explains why there is only 145' of head?  And you comment that its such a shallow well.....isn't there 300' of water below the well pump that would be cooling the pump?  I was thinking that there is a continuous column of water from the bottom of the well at 815' all the way up to the water level below the top of the casing at 33', which would be a column of water 782' long.  And with an 8" hole, that would be ~782 x 2.6 gallons per LF = 2000+ gallons of water in the well being replenished at 10 gallons per minute per the well report.  If water is entering the well above the pump, wouldn't gravity cause it try to flow downwards towards the bottom of the well and be filling up the 300' space between the well pump and bottom of the well, thereby keeping the pump bathed in water, unless the pump depleted the well?  And with the well replenishing at 10 GPM per the well report, and the pump having an average output of 10 GPM, wouldn't it be hard to drain the well?  When I had the problem the other day with the pump turning off, I was running one garden hose for about 20-25 minutes and no other water was being used in the house.

How would two CSV1A's work instead of just one? Would one be set at a higher pressure and the second at the target pressure?  I want to understand the mechanics of what would be happening. The pump I have is a Grundfos 10S15-21

Thanks very much.


Cary Austin

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Re: Just got a new larger well pump and want to keep it healthy
« Reply #3 on: July 07, 2019, 05:28:44 PM »
Water under water doesn't weigh anything.  Even though the pump is set at 500', it is only lifting from 33'.  50 PSI is the same as 115' of head so 115' plus 33' is a total head the pump will see of 148' of head.  As the water level pulls down the head will increase accordingly.  But like you said 2 gallons per foot, a house uses maybe 300 gallons per day, so you are never pulling it down below about 180' or so.  Your water is coming into the casing at 645' and 740'.  But you will need to pull the water level down from the top before any will start coming in from below.  As you are pulling water from above the pump, you can be boiling water 2' lower at the bottom of the motor.  Also the pump should have been cycling on and off while just running one faucet. Either or both of those things can cause an overload to trip.

A 4" shroud or flow inducer over the pump makes water go past the motor and keep it cool even when being fed from the top. 

With such a high head pump and such shallow static water level, the first CSV1A would be set to 150 PSI, and the second would be set to the 50 PSI you want.  That way there is only about 100 PSI difference across either CSV and they will last a long time.

JEG in Raleigh

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Re: Just got a new larger well pump and want to keep it healthy
« Reply #4 on: July 07, 2019, 06:33:33 PM »
Thanks for the explanation. Would I install the two CSV's right before my pressure tank, next to each other, in series? My inlet pipe is 40" long and  vertical, and 90's horizontal right before the pressure tank tee, and connects to the tee with a 5-inch long piece of horizontal pipe.   I don't have room for even one CSV valve attached to the 5-inch long pipe running horizontally, but I do have room to attach both to the vertical pipe.  Can they be installed on a pipe that is running vertically? 

How good of a job will the CSV's do at mitigating the upthrust? 
How would I know if/when a CSV has failed and needed to be replaced?

Thanks.


Cary Austin

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Re: Just got a new larger well pump and want to keep it healthy
« Reply #5 on: July 08, 2019, 07:31:45 AM »
The CSV's can be installed in any position you want.  The only consideration is that all the pipe before the CSV will see the 240 PSI.  You can tell if a CSV has failed because the pump will turn off while you are using water.  With a CSV the pump will continue to run as long as a faucet is open.

Each CSV1A will have about 15 PSI of friction loss.  So two of the CSV1A valves will add 30 PSI or 69' of head to the 148' we already added up.  That would be a minimum head of 217', which shows to keep a 10 GPM, 1HP at less than 16 GPM and below the upthrust limit.

JEG in Raleigh

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Re: Just got a new larger well pump and want to keep it healthy
« Reply #6 on: July 08, 2019, 08:52:37 AM »
My house is on a slab, and the supply line is buried in a wall,  Where it emerges to feed the pressure tank, the pipe material is 1" pex, which the specs seem to say, has a pressure limit of 160 PSI. Are you saying that right now, before I install the CSV, that pipe is being subjected to 240 PSI?

Cary Austin

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Re: Just got a new larger well pump and want to keep it healthy
« Reply #7 on: July 08, 2019, 09:11:47 AM »
Without a CSV all the pipe sees is the 40 to 60 when using a 40/60 switch.  With a CSV all the pipe before the CSV will see 240 PSI because you have such a high head pump with water at 33'.  The pex won't handle that pressure. It would be best to install the CSV's right at the well head before the pex.  The well pipe should be able to handle the pressure, and the pex after the CSV will only see 40 to 60 PSI.

JEG in Raleigh

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Re: Just got a new larger well pump and want to keep it healthy
« Reply #8 on: July 08, 2019, 01:11:26 PM »
Thanks Cary.  I called your company and spoke with a guy to whom I described what I had and the PE piping I had and he said  it would not handle the pressure, so I'm SOL.  I'm going to visit the pump company that put the new well pump in and talk with them about replacing the pump with a smaller one.  This company handles Grundfos and Franklin pumps.  Based on the info I have given you (depth 800', 8" bore, static water level at 30', 120' from the well to the house, and water coming into the casing at 645' and 740', what Grundfos pump would you recommend?

Once I get the pump issue resolved, I'll be contacting you to buy a valve.

Thanks for all your help on this.  It's been an education.

Cary Austin

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Re: Just got a new larger well pump and want to keep it healthy
« Reply #9 on: July 08, 2019, 03:56:42 PM »
That was my son Sam.  Yes 240 PSI is more than i like on even 200# poly pipe.  But I can't believe anyone would set a pump at 500' on poly to start with.  Just at the bottom of 500' you will have 216 PSI, just from the depth.

I would probably set a 10 GPM, 1HP pump at about 300'.  Then the regular PK1A will work and poly pipe can easily handle the pressure.  You don't even have to change the motor.  Just put a 1HP pump end on that 1.5 HP motor and cut off 200' of pipe and wire.

Of course you could always just get a larger or multiple tanks and live with what you have.

JEG in Raleigh

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Re: Just got a new larger well pump and want to keep it healthy
« Reply #10 on: July 08, 2019, 07:14:37 PM »
I actually do have room to add a second pressure tank in the closet behind my utility room. I could fit a tank as large as 81 gallons.

Cary, if you are still game to answer my questions, here is some more info I found on the Grundfos website. Here is a product selection tool they have.   I plugged my numbers into it based on what you had told me.  I have not been able to upload documents to my forum posts, so I am going to email you the screen shot images of what I entered, using their tool.  BTW, here is a link to their tool page.    newbielink:https://product-selection.grundfos.com/front-page.html?sizeType=guided&qcid= [nonactive]       When I plugged my numbers into the product selector, my pump came up as one of the appropriate pumps. 

One piece of info they ask for is the NPSH, which I don't understand, but I found an online calculator for it (big link)  newbielink:https://inventory.powerzone.com/resources/npsh-calculator/%3Aal%3D315%3Aalu%3DFeet%20Above%20Sea%20Level%3Afs%3D1%3Asp%3D470%3Aspu%3DFeet%3Afr%3D10%3Afru%3DGPM%3Avc%3DWater%3Aft%3D68%20Deg~p%20F%20(20C)%3Av%3D0~p999996%3Avu%3DCENTIPOISE%20%2F%20CP%3Asg%3D0~p998%3Avp%3D2~p4%3Avpu%3DKPA%3Apl%3D620%3Aplu%3DFeet%3Apid%3D1%3Apidu%3DInches%3Ahzc%3DPolyethylene%3Ahzfc%3D140%3Arh%3D0~p007%3Arhu%3DMillimeters%3Arfvu%3DFT%2FSec%3Arnu%3DPSI%3Afits%3DTee%2C%20Line%20Flow%7C1!Elbow%2C%2090%C2%B0%20SR%7C1 [nonactive]

I generated an NPSH number using 300' of water below the centerline of the pump and also one using 470' of water above the centerline of the pump.  When I plugged the NPSH numbers generated into the Grundfos product selector, my pump still came up as appropriate.

This is a link to more info on the pump:  newbielink:https://us.grundfos.com/content/dam/GPU/Literature/SP/LSPPG001-0212-SP-ProductGuide.pdf [nonactive]     I'm emailing a screen shot of a blurb from it about a stop ring that they say protects it from upthrust. 

Thanks again.

Cary Austin

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Re: Just got a new larger well pump and want to keep it healthy
« Reply #11 on: July 09, 2019, 07:07:07 AM »
I was assuming the 10S15-21 was the pump you have.  That pump is good if the water pulls down to 300’.  But at 33’ even with 115’ (50 PSI) added is only 148’ of head.  If the water pulls down that pump is needed.  If the water doesn’t pull down very far that pump is way too big.  Either way a big tank is about the best you can do since that pump builds so much pressure with water at 33’.