Shallow well low volume and CSV valve question

[Tom Thompson]

Hello,

First post here. My in-laws have had a shallow well in the same witched stream for about 40 years. it's a low producer, but has worked. We put one in and it worked for 10 years, but then we had problems. We now pounded a new 1 1/4" shallow well about 18 feet down. We can get good water and have tried to develop the well by running the system. However, we are having an issue with this new well. I am not sure of the exact terms, but when the water in the well casing is used up, and the water flow going into the casing can't keep up, the pump keeps running, but gets very hot. Water barely comes out of the faucets, then it will stop all together and the pump stays running. We then have to let the pump sit until it cools, and re-prime the pump to get it going again. Currently running a Menards Little Giant 3/4 hp pump with a 13 gallon attached pressure tank. Pressure switch is factory set at 30/50.

Let me know if you like my plan, or you think there is a better plan. My plan to solve this is to use a cycle stop valve. I believe what is happening is that the well is running dry with all the water use and having a pump trying to pump at 13 GPM. I am going to add a larger pressure tank to hold water so it can be used and not have the pump turn on as often. Then when the pump does come on the CSV will allow only 1 GPM (rather than the pumps 13 gpm) to slowly pull water back in to refill the pressure tank. This will allow the low yield well to keep up with the pump. Hopefully stopping it from taking too much water and then sitting running getting hot. I also plan on adding a Square D low pressure switch, in case the water does run out, the pump doesn't sit and run. I realize this requires going out and manually resetting the switch in the pump house, but it's better than having the pump get hot and having to re-prime it.

I am also thinking of pounding a second 1 1/4" well casing down and connecting the two before the pump to have an extra bit of water to draw from.

Another thought is to get a better pump, either a Gould 1/2 HP or a A.Y. McDonald 1/2 HP. any thoughts on if these may not have some of the same issues I'm experiencing with the Menards Little Giant pump?

What do you think of these ideas and do you have any other ideas that may help?

 

[Valveman]

Another pump won't help if the well can't produce enough water. Adding another point or two should double or triple the amount of water the pump can access. A CSV will help as it won't pump the well dry while filling the tank at 1 GPM. But a larger tank will act like another demand for water and will make things worse. If another point or two doesn't help, a cistern storage tank with a booster pump would be needed.

 

[Sponsor]

 

[Reach4]

You might consider having a bigger well put in. Not cheap, but you might call a driller or two in the area for a budgetary price. It may accept water better, plus bigger diameter would serve as as some storage. This would have a submersible pump and pitless adapter. If it does not let you not need the storage tank, then it is probably not worth doing.

The thing that will limit the rate that a pump can pump is called a Dole valve. I am not confident that would keep that well from sucking dry. The shut-down device like Cycle Sensor protects the pump by shutting down the pump for a settable interval if you run out of water.

 

[Tom Thompson]

Another pump won't help if the well can't produce enough water. Adding another point or two should double or triple the amount of water the pump can access. A CSV will help as it won't pump the well dry while filling the tank at 1 GPM. But a larger tank will act like another demand for water and will make things worse. If another point or two doesn't help, a cistern storage tank with a booster pump would be needed.
View attachment 54381

Thank you for the reply. I should add that we have had about 5-7 feet of water in the 1 1/4" line, when we measure it down the pipe. This new 1 1/4" line was put in last week. With a hand pump we are able to continually bring up water without any issues. I have used the regular hand pump with both the brass check valve on and with it off when using the hand pump. The water has cleared up nicely and is pumping very well. When this started, we were checking the GPM, by fillling a 5 gallon bucket and timing it. We were able to fill the bucket 3 times from an outdoor spigot valve, and then it took about a minute and a half (or a little less) to refill the 13 gallon pressure tank (about 3-4 gallon water). The tests were all done right in sequence, so probably within 15 minutes total time. Then we were able to do laundry and showers and everything was fine. About 8 hours later, after no water use, we started laundry and the dishwasher again. a few minutes later I went to the kitchen sink, turned on the faucet and realized there was very little flow and pressure. Went down to the pump house and that's when the pump was really hot and not sucking water up anymore.

My wife said that the water at the spigot looked bubbly, like possibly an air leak on the suction side. I checked the suction side and couldn't find an air leak. We have a brass check valve sitting vertically on the 1 1/4 pipe coming out of the ground. Then we have a short run of PVC with a PVC union, an elbow and then a short run of PVC to the inlet of the pump.

Not sure if this information would change your recommendations? Also, what I was reading about adding the bigger/extra pressure tank(s) for more storage when the peak demand is going, and then using the CSV valve was so that the pump would basically be throttled at 1 GPM while working to fill the pressure tank after it had been drawn down. Would that still be the extra draw you were describing, making things worse?

Thanks Tom

 

[Tom Thompson]

You might consider having a bigger well put in. Not cheap, but you might call a driller or two in the area for a budgetary price. It may accept water better, plus bigger diameter would serve as as some storage. This would have a submersible pump and pitless adapter. If it does not let you not need the storage tank, then it is probably not worth doing.

The thing that will limit the rate that a pump can pump is called a Dole valve. I am not confident that would keep that well from sucking dry. The shut-down device like Cycle Sensor protects the pump by shutting down the pump for a settable interval if you run out of water.

Hello,

Thanks for the reply. We called multiple well drillers in the area. They all said they were so busy they weren't interested in a "toy well", since they were staying busy doing deep wells. Got one driller to quote a minimum price of $7500 to come and try, but it would be at least 4-6 months out. None of the rest wanted to even give a quote because they were so busy and doing deep wells. If you know of a well driller on the Wisconsin side, north of the Minneapolis/St Paul area let me know, because I called lots of them.

Is the Cycle Stop Valve what you refer to as a Dole valve?

Thanks, Tom

 

[Valveman]

A pump doesn't come on until the pressure tank is empty. Then the pump sees the tank as another load to fill on top of the water you are using. You can set a CSV to fill the entire tank at 1 GPM, so it doesn't pump the well dry while filling the tank. But you really don't want the pump to run longer than 3 minutes or so to fill the tank, or you are wasting energy. So a 13 gallon tank that holds about 3-4 gallons is as big as you want.

 

[Valveman]

A CSV will vary to allow the pump to produce as much as you are using. A Dole valve has a set flow rate like 3 GPM, so the pump can never pump over 3 GPM. They make Dole valves in different flow rates up to about 90 GPM.

 

[Reach4]

Is the Cycle Stop Valve what you refer to as a Dole valve?

The cycle stop valve can flow much more than 13 gpm when the output pressure is below the setpoint. At pressures above the setpoint, the CSV restricts flow.

Trying to store water in the pressure tank is not going to do it for you. What if the pressure tank was almost empty when the pump kicked on?

A 3 GPM Dole valve would limit the flow through the pump to about 3 gpm at all times. I think that at 3 gpm, your well would still pump dry.

 

[Jadnashua]

It was suggested earlier...to be able to have water on demand, you need a larger storage tank (a cistern) that could be filled slowly, then pump it out of the storage tank. If sized properly, you could also have enough water to help fire fighters, should that need ever arise, too.

Letting your pump run dry will severely shorten its life. A small pump feeding the tank would likely use less energy and be cheaper to buy.

 

[Tom Thompson]

Another pump won't help if the well can't produce enough water. Adding another point or two should double or triple the amount of water the pump can access. A CSV will help as it won't pump the well dry while filling the tank at 1 GPM. But a larger tank will act like another demand for water and will make things worse. If another point or two doesn't help, a cistern storage tank with a booster pump would be needed.
View attachment 54381

Let me make sure I understand how the CSV valve works. It starts out like a normal draw from the pressure tank and uses up whatever amount is in that pressure tank first. Then once that gallon (or 10 gallons, etc) is gone, it starts to allow water through at whatever rate it is being drawn at (a toilet flush, a shower at 2.5 gpm, etc), however it isn't having water going back into the pressure tank, it's bypassing that and just sending water to the user. Then once the use draw is done, the CSV throttles the flow down to 1 GPM to refill the pressure tank.

So the difference between a Dole valve that always throttles down the flow to whatever rate and the CSV valve, is that the CSV allows full use to the fixtures when being drawn, but throttles down the draw, after the usage draw is done, to refill the pressure tank?

So for a slow refilling or low yield well why wouldn't you want to have a larger pressure tank with the CSV? Wouldn't that mean you would have water reserved in the pressure tank for the high demand showers, toilet, shave, etc and then it would slowly (1 gpm) refill the bigger tank after the use is done? That way the tank is being refilled after the use at a slow rate?

Thanks Tom

 

[Reach4]

We called multiple well drillers in the area. They all said they were so busy they weren't interested in a "toy well", since they were staying busy doing deep wells. Got one driller to quote a minimum price of $7500 to come and try, but it would be at least 4-6 months out. None of the rest wanted to even give a quote because they were so busy and doing deep wells.

This might be a good place for a "dug well". Search out the term. It would combine storage into the well.

I was looking for something similar to https://www.health.state.mn.us/communities/environment/water/docs/wells/construction/handbook.pdf for Wisconsin.

 

[Valveman]

Let me make sure I understand how the CSV valve works. It starts out like a normal draw from the pressure tank and uses up whatever amount is in that pressure tank first. Then once that gallon (or 10 gallons, etc) is gone, it starts to allow water through at whatever rate it is being drawn at (a toilet flush, a shower at 2.5 gpm, etc), however it isn't having water going back into the pressure tank, it's bypassing that and just sending water to the user. Then once the use draw is done, the CSV throttles the flow down to 1 GPM to refill the pressure tank.

So the difference between a Dole valve that always throttles down the flow to whatever rate and the CSV valve, is that the CSV allows full use to the fixtures when being drawn, but throttles down the draw, after the usage draw is done, to refill the pressure tank?

So for a slow refilling or low yield well why wouldn't you want to have a larger pressure tank with the CSV? Wouldn't that mean you would have water reserved in the pressure tank for the high demand showers, toilet, shave, etc and then it would slowly (1 gpm) refill the bigger tank after the use is done? That way the tank is being refilled after the use at a slow rate?

Thanks Tom

That is a very good explanation. However, you don't want it to take too long to fill the tank. So with a large tank and a 40/60 pressure switch the CSV would be set at 55 to 57 PSI. That way the tank is filled to 55 PSI at max pump rate, the CSV holds the pressure at 55 PSI for as long as you are using water, then the CSV tops off the tank from 55 to 60 when all the faucets are shut off. With a weak well the extra volume in a large tank is just taking more out of the well, and maybe more than there is available.

You could make it fill the entire tank at 1 GPM by setting the CSV to 40 PSI. But that would take 20 minutes to fill a 20 gallon draw tank, and would really be wasting 18 minutes of electricity. Pressure tanks are not for storage. Pressure tanks only job is to keep the pump from cycling, and when you have a CSV to do that for you, a large tank is not needed.

Another disadvantage of a large tank, is that while you are using water from the tank the pressure is continually decreasing from 60 all the way down to 40 PSI. With a small tank the pump is on and the shower pressure is a strong constant 50 PSI from the start, and will stay strong even if you are in the shower for a month.

 

[Tom Thompson]

That is a very good explanation. However, you don't want it to take too long to fill the tank. So with a large tank and a 40/60 pressure switch the CSV would be set at 55 to 57 PSI. That way the tank is filled to 55 PSI at max pump rate, the CSV holds the pressure at 55 PSI for as long as you are using water, then the CSV tops off the tank from 55 to 60 when all the faucets are shut off. With a weak well the extra volume in a large tank is just taking more out of the well, and maybe more than there is available.

You could make it fill the entire tank at 1 GPM by setting the CSV to 40 PSI. But that would take 20 minutes to fill a 20 gallon draw tank, and would really be wasting 18 minutes of electricity. Pressure tanks are not for storage. Pressure tanks only job is to keep the pump from cycling, and when you have a CSV to do that for you, a large tank is not needed.

Another disadvantage of a large tank, is that while you are using water from the tank the pressure is continually decreasing from 60 all the way down to 40 PSI. With a small tank the pump is on and the shower pressure is a strong constant 50 PSI from the start, and will stay strong even if you are in the shower for a month.

I have one last question (well at least I think so now). Using the CSV and taking a 20 minute shower, the pump runs for 20 minutes. If you have an 80 gallon pressure tank (20 gallon draw down), the pump doesn't come on until you've used the 20 gallons. I understand that the pressure is decreasing from 60 to 40 during the drawdown. Then the pump comes on. If you make the CSV not fill the tank but stay at 40 psi, then the shower pressure would not change. When the shower is shut off the 20 gallons in the tank would be filled, and it would take 20 minutes.

Both ways the pump is running for about 20+ minutes. Using the water with a low flow shower of 2 gpm, would take 10 minutes to use up the drawdown, and then 20 minutes to refill the tank. If you take a 20 minute shower with a 2 gpm flow shower, the pump will be on basically the whole 20 minutes and shut off a couple minutes after the shower shuts off. Very similar length of pump use and no cycling on and off in either scenario.

With a low yield well wouldn't it be better to use the 1 gpm tank refill rather than sucking 2 gpm for the shower from the well. I understand the pressure differences, I'm asking more about the well water usage issue.

Thanks, Tom

 

[Reach4]

With a low yield well wouldn't it be better to use the 1 gpm tank refill rather than sucking 2 gpm for the shower from the well.

The big tank will refill at 7 to 12 gpm (depends on pump and water depth) minus the 2 gpm if the shower is still going on.

 

[Valveman]

You could do that using a 1 GPM Dole valve. And as long as the tank is full when you start to use water that will work. But if the water in the tank has been used for flushing, washing hands, etc, and the tank is down to say 45 PSI, then you would only have enough water for a 5 minutes shower before the tank is empty. I know of one guy that made that work. But he put a timer on the pump to make it come on every few minutes if the pressure was not already at 60. That way he always had a tank full. But I don't know what he was using to turn the pump on and still be letting the pressure switch shut the pump off?

 

[Valveman]

The big tank will refill at 7 to 12 gpm (depends on pump and water depth) minus the 2 gpm if the shower is still going on.

He is talking about setting the CSV so the whole tank fills at 1 GPM. There really is no substitute for a storage tank when your well only makes 1 GPM.

 

[Tom Thompson]

Well an update. I took the PVC joint out of the suction side and just screwed the two pieces in tight and then glued an elbow in, to reduce the possibility of suction side leaks. Added a 1" ball valve and 1 1/4" female threaded joint at the top of the prime tube/out tube. That way I can fill the pump up from the primer tube and then use my hand pump to prime all the way up the well and through the pump. Then I can close the ball valve. It worked great, what used to take 20 or 30 minutes or didn't work, now took 2 minutes. I still have a couple drips on the out side that I will work on but for now the well is keeping up with everything I am doing again. Perhaps it was as just leaks on the suction side causing problems. I'll know more as a couple days go by and see how it works.

 

[Valveman]

A suction leak will make it act like you are running out of water.