Traveller
Member
Hello valveman
Do they make cycle stop valve systems capable of handling 40-50 gpm from a submersible pump?
Do they make cycle stop valve systems capable of handling 40-50 gpm from a submersible pump?
To valveman re: cycle stop valve
- Thread starter Traveller
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Sure. We have CSV's that can handle a 5,000 GPM pump. There are a couple of options for a 50 GPM pump. What kind of pump do you have? Model number and/or horsepower would be good if you have it?
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Traveller
Member
The pump belongs to a customer I do work for. It is an unusual setup and I will try to describe it to you.
The pump is a Myers SS30-50-01 (3 hp 50 gpm) coupled to a Pentek Model no. P43B0030A3 (3 hp 3 phase) motor. The well is a drilled well with a 6" casing that is 55' below ground level to finished depth. The pump intake is 51' 4" below ground level and the water table is 17' 11" below ground level. The drilling profile shows the well to be in gravel and coarse sand and there is virtually no drawdown as the well recharges almost instantaneously. A 2" poly line, connected with hose clamps, delivers the water to a pumphouse 8' away from the wellhead where the pump is controlled by a Pentek Intelli-Drive and a 14 gallon bladder tank.
The Pentek Intelli-Drive has given the owner nothing but grief since it was installed almost a year ago and he has had to rely, for a good part of that time, on a 2 hp jet pump drawing from the original 23' dug well that is in the same pumphouse. Although no one here, myself included, claims to understand the Intelli-Drive, it is felt that the numerous power bumps we experience here are part of the problem. No surge arrestor was ever installed on this Intelli-Drive and the company that installed this setup seems reluctant to come back and service it.
The owner does not require a high pressure (50 psi would be adequate) but, in the summer months, he does require a large volume of water, as he has about 10 acres of property and most of it is covered in lawn and gardens in very gravelly porous soil. This is why the 50 gpm pump was installed, I believe. The entire property is quite level and sited at sea level.
The pump is a Myers SS30-50-01 (3 hp 50 gpm) coupled to a Pentek Model no. P43B0030A3 (3 hp 3 phase) motor. The well is a drilled well with a 6" casing that is 55' below ground level to finished depth. The pump intake is 51' 4" below ground level and the water table is 17' 11" below ground level. The drilling profile shows the well to be in gravel and coarse sand and there is virtually no drawdown as the well recharges almost instantaneously. A 2" poly line, connected with hose clamps, delivers the water to a pumphouse 8' away from the wellhead where the pump is controlled by a Pentek Intelli-Drive and a 14 gallon bladder tank.
The Pentek Intelli-Drive has given the owner nothing but grief since it was installed almost a year ago and he has had to rely, for a good part of that time, on a 2 hp jet pump drawing from the original 23' dug well that is in the same pumphouse. Although no one here, myself included, claims to understand the Intelli-Drive, it is felt that the numerous power bumps we experience here are part of the problem. No surge arrestor was ever installed on this Intelli-Drive and the company that installed this setup seems reluctant to come back and service it.
The owner does not require a high pressure (50 psi would be adequate) but, in the summer months, he does require a large volume of water, as he has about 10 acres of property and most of it is covered in lawn and gardens in very gravelly porous soil. This is why the 50 gpm pump was installed, I believe. The entire property is quite level and sited at sea level.
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The CSV was designed to replace VFD’s. We have been replacing VFD’s with CSV’s everyday for the last 20 years. People think the VFD is new technology. In reality the VFD is decades older technology than the CSV. Just because something is electronic and complicated doesn’t mean it is newer or better technology than something simple and mechanical. Just the opposite is true. Newer and more beneficial technology means being able to do more with less, not doing less with more.
A CSV will make the system simple, which is the best way to keep it reliable. Your problem with switching this system from a VFD to a CSV is the three-phase motor. They use the VFD to convert single phase to three-phase, claiming it is more efficient and saves you money on wire size compared to single-phase. In reality it locks you into having to repair (replace!!) the VFD, unless you want to change the motor out to single-phase.
Unless you have three-phase power available at the house, the motor will need to be switched over to single-phase to work with a CSV. There are two different CSV’s that will work with that pump. The first is a CSV1.25-50, which sell for about $111.00. The next one is a municipal grade, adjustable, heavy-duty valve model CSV3B2T, which sells for about $650.00. They will both work the same way. The latter is just a longer lasting, heavy duty, adjustable version.
Because they are stuck with the three-phase motor, many people will repair or replace the VFD controller a few times, then wish they had made the change to a CSV much earlier. You are better off to bite the bullet now, and get a CSV so the water system can become dependable.
A CSV will make the system simple, which is the best way to keep it reliable. Your problem with switching this system from a VFD to a CSV is the three-phase motor. They use the VFD to convert single phase to three-phase, claiming it is more efficient and saves you money on wire size compared to single-phase. In reality it locks you into having to repair (replace!!) the VFD, unless you want to change the motor out to single-phase.
Unless you have three-phase power available at the house, the motor will need to be switched over to single-phase to work with a CSV. There are two different CSV’s that will work with that pump. The first is a CSV1.25-50, which sell for about $111.00. The next one is a municipal grade, adjustable, heavy-duty valve model CSV3B2T, which sells for about $650.00. They will both work the same way. The latter is just a longer lasting, heavy duty, adjustable version.
Because they are stuck with the three-phase motor, many people will repair or replace the VFD controller a few times, then wish they had made the change to a CSV much earlier. You are better off to bite the bullet now, and get a CSV so the water system can become dependable.
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Traveller
Member
Thank you for the reply. Unfortunately, only single phase power is available at this location. However, in order to make the well functional, the owner is willing to purchase a single phase motor for the pump. I had been looking at installing a 30-50 pressure switch and bladder tank but, considering the gpm potential of this pump, it would require a very large bladder tank(s) to allow the pump to have a 1-2 minute run time each time it came on.
I was looking at the animation comparing the CSV system to a regular pressure switch/large bladder tank system. From what I can gather, everything in the CSV system operates identical to a pressure switch system, when a tap is opened, until the pressure drops to the cut-in pressure of the CSV's pump switch. Correct me if I am misinterpreting what I see but, at this point, it appears access to the bladder tank is cut off and the CSV meters a constant flow, dictated by demand, to the house. It also appears that pressure between the pump and the CSV can go as high as 130 psi and will drop as low as 60 psi as more devices ask for more water.
Please understand that I mean no disrespect by the next question, and the fact that these devices have been successfully installed for 20 years speaks for itself but, is there not a great potential for a water hammer between the CSV and the pump at the moment of startup, with access to the bladder tank being shut off? I only ask this because of a similar experience I had with a 5 hp submersible pump. I operate the water system for the village of 300 I live in. We have three wells (entire system at sea level) that each feed into the main 10" pipeline through their own branchlines. We also have a 130,000 gallon reservoir 220' above sea level that gives us a static gravity feed pressure of 94 psi throughout the system. The three pumps are turned off and on by float switches in the reservoir set at 75% and 100%. When the pumps start, they are required to start against this 94 psi backpressure, with no relief from any kind of air tank or relief valve. When our largest pump, a 5 hp submersible, started up, there was a vicious water hammer that would rattle all the plumbing in the pumphouse and bury the needles in both directions on the pressure gauges repeatedly. This went on until underground piping in the contact chamber outside the pumphouse let go. To solve the problem, we installed a VFD and 3 phase motor, but not as a constant pressure system. The VFD is only programmed as a "soft start" to start and stop the pump over six seconds instead of having the pump trying to come up to 3450 rpm in a fraction of a second.
As I said, please do not take offense at my question regarding water hammer as I am sure there is something in the CSV application I am missing.
I was looking at the animation comparing the CSV system to a regular pressure switch/large bladder tank system. From what I can gather, everything in the CSV system operates identical to a pressure switch system, when a tap is opened, until the pressure drops to the cut-in pressure of the CSV's pump switch. Correct me if I am misinterpreting what I see but, at this point, it appears access to the bladder tank is cut off and the CSV meters a constant flow, dictated by demand, to the house. It also appears that pressure between the pump and the CSV can go as high as 130 psi and will drop as low as 60 psi as more devices ask for more water.
Please understand that I mean no disrespect by the next question, and the fact that these devices have been successfully installed for 20 years speaks for itself but, is there not a great potential for a water hammer between the CSV and the pump at the moment of startup, with access to the bladder tank being shut off? I only ask this because of a similar experience I had with a 5 hp submersible pump. I operate the water system for the village of 300 I live in. We have three wells (entire system at sea level) that each feed into the main 10" pipeline through their own branchlines. We also have a 130,000 gallon reservoir 220' above sea level that gives us a static gravity feed pressure of 94 psi throughout the system. The three pumps are turned off and on by float switches in the reservoir set at 75% and 100%. When the pumps start, they are required to start against this 94 psi backpressure, with no relief from any kind of air tank or relief valve. When our largest pump, a 5 hp submersible, started up, there was a vicious water hammer that would rattle all the plumbing in the pumphouse and bury the needles in both directions on the pressure gauges repeatedly. This went on until underground piping in the contact chamber outside the pumphouse let go. To solve the problem, we installed a VFD and 3 phase motor, but not as a constant pressure system. The VFD is only programmed as a "soft start" to start and stop the pump over six seconds instead of having the pump trying to come up to 3450 rpm in a fraction of a second.
As I said, please do not take offense at my question regarding water hammer as I am sure there is something in the CSV application I am missing.
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The CSV is a very simple valve. Unfortunately the explanation of how a CSV works can be complicated. Let me take this one thing at a time.
The CSV can’t do anything until the pump is started. When a tap is opened, the pressure tank will drain from 60 to 40 PSI, and the pressure switch will start the pump. With a CSV setting of 50 PSI, the tank is refilled half way to 50 PSI before the CSV starts to work. At that point the CSV supplies flow according to the demand. If the pressure increases to 51 PSI, the CSV restricts the flow. If the pressure drops to 49 PSI, the CSV opens up to deliver more flow. In this way the pressure controls the CSV as there is no electricity connected to the CSV. When there is no more water being used, the CSV closes as much as it can at 51 PSI. However, depending on the size of the CSV, it can’t close to less than 1 to 5 GPM. At this point the 1 to 5 GPM passing through the CSV has no place left to go except the pressure tank. Then the pressure gradually increases as the last half of the pressure tank is filled to 60 PSI and the pressure switch shuts off the pump.
Not starting against enough pressure was the cause of your water hammer experience. At 94 PSI, that pump was still able to supply about 50 GPM. So the pump started at 50 GPM. Trying to instantly force 50 GPM into the system is what caused the water hammer. No water hammer is created when you start a pump against a closed or almost closed valve, as with a CSV. The CSV will instantly open up to supply the 50 GPM when needed, but the shock of 50 GPM trying to be forced into the system is eliminated by the CSV. The pump actually starts at 120 or 150 PSI. This makes it start at 5 GPM, instead of 50 GPM, and the water hammer is eliminated.
It is hard for a VFD to slow start a pump slow enough to prevent water hammer. Head or pressure increases by the square of the RPM. So with a 6 second start up, the first 5 seconds won’t spin the pump fast enough to even open the check valve. Then the last second of the 6 the head or pressure increases rapidly, and you can still have water hammer.
Soft starting a submersible with a VFD can greatly shorten the life of the motor. Submersible motors needs to be spinning a minimum of 50% speed to cool and lubricate the Kingsbury type thrust bearing. So for 3 of the 6 seconds during a 6 second start, the bearing is running dry. It doesn’t take very long for the thrust bearing to fail when running dry for 3 seconds on each start up.
Also taking 6 seconds to start means the pump/motor is slowly going through several critical speeds, which cause resonance vibrations and prematurely destroy the pump.
The CSV gives a mechanical soft start and soft stop, without varying the speed of the pump/motor. This allows the thrust bearing to get lubrication instantly. The CSV also does not let the pump run at any critical speeds, so there is no resonance vibration.
The CSV does a better job at preventing water hammer than a VFD, and it does it for a fraction of the cost.
Traveller
Member
That seems to make a lot of sense, although my brain is still trying to sort through all of the details. I think what you are telling me is that the CSV does not allow a water hammer to take place?
Traveller
Member
Okay, Mr. Valveman, now you have REALLY got my attention LOL.
Are you saying the CSV can be used as a soft start and soft stop and even the more expensive municipal model was a mere $650?? We paid over $2000 for the VFD and a crook of an electrician charged us another $2000 to install it and the 3 phase pump motor, with me doing all of the grunt work.
Luckily, the technician that coached us through the setup knew a bit about motor cooling. We have it programmed to come up to 30 cycles in the first second and up to the full 60 cycles in five more seconds. It was necessary to install a 6" flow inducing shroud on the pump to maintain an optimum cooling flow inside the 8" well casing. There is still a visible surge of about 30 psi on the gauge, although an engineer told me the average gauge is not quick enough to measure water hammer and the real hammer would be several factors greater than the 30 psi seen on the gauge.
Nonetheless, you are correct in saying the CSV is a simple mechanical device that is easily and cheaply replaced, should replacement be necessary. Every time I go into that pumphouse and see that computerized VFD hanging on the wall, I think about our remote location (a group of islands 100 miles south of Alaska) and our total inability to repair or service this VFD should it break down.
I will pass this information on to the committee members for our water system plus my customer with the non-functioning Pentek Intelli-Drive.
Are you saying the CSV can be used as a soft start and soft stop and even the more expensive municipal model was a mere $650?? We paid over $2000 for the VFD and a crook of an electrician charged us another $2000 to install it and the 3 phase pump motor, with me doing all of the grunt work.
Luckily, the technician that coached us through the setup knew a bit about motor cooling. We have it programmed to come up to 30 cycles in the first second and up to the full 60 cycles in five more seconds. It was necessary to install a 6" flow inducing shroud on the pump to maintain an optimum cooling flow inside the 8" well casing. There is still a visible surge of about 30 psi on the gauge, although an engineer told me the average gauge is not quick enough to measure water hammer and the real hammer would be several factors greater than the 30 psi seen on the gauge.
Nonetheless, you are correct in saying the CSV is a simple mechanical device that is easily and cheaply replaced, should replacement be necessary. Every time I go into that pumphouse and see that computerized VFD hanging on the wall, I think about our remote location (a group of islands 100 miles south of Alaska) and our total inability to repair or service this VFD should it break down.
I will pass this information on to the committee members for our water system plus my customer with the non-functioning Pentek Intelli-Drive.
Again the CSV will do a better job of eliminating water hammer than a VFD. With the CSV you would not see that 30 PSI bounce you are seeing now. And yes water hammer is usually 5 to 10 times the pressure you see on the gauge. So a 30 PSI bounce could still be a 300 PSI water hammer.
You are going to hate what I have to tell you next. You said they also changed the motor to three-phase? That is because a VFD only works with a three-phase motor. (for the most part) So now they are using the VFD to convert the single-phase power to three-phase for the three-phase motor. This basically locks you into a continual pattern of replacing the VFD. Unless you switch back to a single-phase motor or have three-phase power brought into the system, you are stuck with the VFD.
Notice I said “replace” the VFD, not repair. Your worry about not being able to work on a VFD is unfounded, as no one can work on a VFD. They are made to be replaced, not repaired. So you just need to purchase another $2,000 drive and have it ready for emergencies. Because the VFD will quit you in short order, and always at the most inopportune time.
Keeping a spare VFD is the best way to be prepared for the inevitable emergency. However, the VFD also causes high voltage spikes to the motor, resonance frequency vibration, and harmonics. In above ground motors a VFD also causes EDM or destructive electrical currents to the motor bearings, and other things. With submersibles, the longer the wires down to the motor, the higher the voltage spikes the motor will see. The VFD causes a reflective wave that is amplified by the length of wire. So a 240V motor will regularly see over 1,000 volts. And a 480 volt motor will see over 2,000 volts. So being as your system is so remote, you might also need to keep a spare motor on hand.
The CSV doesn’t care what power the pump is running on. It will work with a single-phase pump just as well as a three-phase pump. The CSV doesn’t cause the premature destruction of the motor in anyway. As a matter of fact the CSV will greatly increase the life of the pump and motor, which is exactly why they sold you a VFD instead.
Even though the new VFD’s will let you get the motor to 50% speed in 1 second, then wind up to full speed in 5 more seconds, the pump still goes from a no flow speed to a speed that delivers too much flow very quickly. That is why you are still seeing the 30 PSI bounce, which is still causing some water hammer.
I didn’t mean the CSV was a simple mechanical device, which “makes it easy to replace if needed”, even though that is true. I meant the CSV is a very simple device to have such a complicated explanation.
If you want the system to be dependable, you should change back to the single-phase motor, remove the VFD, and add a Cycle Stop Valve. Otherwise the VFD will cause you to be out of water at the worst time, be expensive to repair, and still has not completely eliminated the water hammer problem.
You are going to hate what I have to tell you next. You said they also changed the motor to three-phase? That is because a VFD only works with a three-phase motor. (for the most part) So now they are using the VFD to convert the single-phase power to three-phase for the three-phase motor. This basically locks you into a continual pattern of replacing the VFD. Unless you switch back to a single-phase motor or have three-phase power brought into the system, you are stuck with the VFD.
Notice I said “replace” the VFD, not repair. Your worry about not being able to work on a VFD is unfounded, as no one can work on a VFD. They are made to be replaced, not repaired. So you just need to purchase another $2,000 drive and have it ready for emergencies. Because the VFD will quit you in short order, and always at the most inopportune time.
Keeping a spare VFD is the best way to be prepared for the inevitable emergency. However, the VFD also causes high voltage spikes to the motor, resonance frequency vibration, and harmonics. In above ground motors a VFD also causes EDM or destructive electrical currents to the motor bearings, and other things. With submersibles, the longer the wires down to the motor, the higher the voltage spikes the motor will see. The VFD causes a reflective wave that is amplified by the length of wire. So a 240V motor will regularly see over 1,000 volts. And a 480 volt motor will see over 2,000 volts. So being as your system is so remote, you might also need to keep a spare motor on hand.
The CSV doesn’t care what power the pump is running on. It will work with a single-phase pump just as well as a three-phase pump. The CSV doesn’t cause the premature destruction of the motor in anyway. As a matter of fact the CSV will greatly increase the life of the pump and motor, which is exactly why they sold you a VFD instead.
Even though the new VFD’s will let you get the motor to 50% speed in 1 second, then wind up to full speed in 5 more seconds, the pump still goes from a no flow speed to a speed that delivers too much flow very quickly. That is why you are still seeing the 30 PSI bounce, which is still causing some water hammer.
I didn’t mean the CSV was a simple mechanical device, which “makes it easy to replace if needed”, even though that is true. I meant the CSV is a very simple device to have such a complicated explanation.
If you want the system to be dependable, you should change back to the single-phase motor, remove the VFD, and add a Cycle Stop Valve. Otherwise the VFD will cause you to be out of water at the worst time, be expensive to repair, and still has not completely eliminated the water hammer problem.
Traveller
Member
Very good explanation. I have just one more question regarding the CSV, before I am totally converted.
In the case of the customer I first discussed, the one with the 3 hp, 50 gpm submersible pump feeding his irrigation system and the house he lives in, if he was to open a tap on a sink and let it run until the cut in pressure of the pump was reached, the pump would be running but only a fraction of its 50 gpm potential would be coming out of the faucet on the sink. Would there be an adequate amount of water going past the motor on the submersible pump to keep it cooled?
In the case of the customer I first discussed, the one with the 3 hp, 50 gpm submersible pump feeding his irrigation system and the house he lives in, if he was to open a tap on a sink and let it run until the cut in pressure of the pump was reached, the pump would be running but only a fraction of its 50 gpm potential would be coming out of the faucet on the sink. Would there be an adequate amount of water going past the motor on the submersible pump to keep it cooled?
Masterpumpman
In the Trades
I worked for CSV for seven years and it works as Cary said. I love the CSV's and recommend them to everyone. The VFD's are expensive and troublesome. Try the CSV. . . I promise you and your customers will love it. I talk to many home owners and installers that tell me that they replaced their VFD with a CSV and will never use a VFD again.
A 3HP pump/motor needs about 3 GPM flowing to remain cool. The minimum needed to cool the pump/motor is built into the CSV. That size CSV just can’t close to less than 3 GPM. If the faucet is only using 1 GPM, the other 2 GPM go into the pressure tank until the pump shuts off. When the 1 GPM faucet drains the water out of the tank, the pressure switch re-starts the pump and the process is repeated.
Basically if you are using less than 3 GPM, the CSV makes the pump act like a 3 GPM pump, which slowly cycles on/off using a small pressure tank. The minimum size tank I would use with this size valve is a 20 gallon tank that holds 5 gallons of water. The one GPM faucet would cause the pump to cycle on for about 2 minutes and be off for 5 minutes. This is a slow enough cycle that is doesn’t hurt anything.
Of course any flow rate over 3 GPM and the CSV will keep the pump running constantly.
Traveller
Member
Thank you for that answer, valveman. Coincidentally, I just finished reading this excellent article that supports your argument and explains it all in terms of reduced amperage draw.
http://www.pressurepak.com/cyclestop/techinfo.html
http://www.pressurepak.com/cyclestop/techinfo.html
