I’m on a private well and looking for ways to take it easy on the extremely new 1-1/2 HP submersible pump set at 250′, static at 126′. I have a pressure tank, a bladdered Flotec 120-gallon-equivalent, set to 38 psi. The pressure switch is set to 40-60 psi.
I ran across “cycle stop valves” in my reading today and could only find one reference on BT. After perusing the Cycle Stop forum and reading glowing case histories, i have to wonder why everyone isn’t using them to further protect pumps and provide constant pressure. I’m planning to use my well to pump water for a sprinkler system and know about sizing sprinkler output to pump output, but it seems this would be a fairly inexpensive insurance policy.
Anyone use them? What version? What problem did you solve? Do they function as advertised?
http://www.cyclestopvalves.com/forum/viewforum.php?f=5&sid=ee0a162f4a1b0bbfaeed30f4d6552298
http://www.pumpsandtanks.com/Tanks/cycle_stop_valves.htm
Replies
Hi SG,
Quick answer, it depends on your water needs.
In another life, I designed residential and agricultural water systems. I sold several of the Cycle Stop valves. In general, they work as advertised. But,,,,,, they are not for every application.
If you are using your system for long term irrigation, they are not very efficient. We referred the them as a poor man's VFD (variable frequency drive). For a simple houshold well pump used as an irrigation source say once a week for several hours, then I would say yes, consider it. For much longer periods, there are other options. Franklin Electric made a soft start control panel which operated like a VFD. They were pretty pricey 7 years ago.
You mentioned a new sub. You might need to lift your pump and install a cooling sleeve depending on your well casing size. Franklin Electric has very specific requirements on water flow for motor cooling. If a 4 inch diameter motor is in a 6 inch diameter well casing and the flow is throttled to a gallon or two per minute, you could in some cases ruin your new motor. What is done in that case is install a 4 inch cooling sleeve over the motor and pump assembly to increase the velocity of the water around the motor to offset the low output of the pump.
Can you adjust your sprinklers or demand so that the pump runs continuously at about 30-35 psi? That would be the cheapest route, assuming the well will produce enough water. Adding another tank might be a better option.
Good Luck!
Frank
I noticed that they did not have any mention of how they worked.And I looked in their "forum". I look at a couple of "threads" which where just single messages posted by the moderator attacking VFD's.In a different life I used to do the software to control water distribution systems (mostly small and rural). We controlled a lot of VFD pumps along with a number of multi-staged pumps. At first they where mostly on systems that did not have tanks and we used system curves to command head end pressures based on flows to maintain pressure at the far end.But then I noticed that we where controlling a number of VFD's as part of series of staged pumps on more conventional systems. On those I did not control the speed. Not sure, but I think that typically they where preset by the operators.Never did any VFD's on wells. In fact did not control too many wells. But when I did they often required custom controls. In one we had to balance the flow from several different well fields because of the water quality. Had to balance how much was coming from each one..
William the Geezer, the sequel to Billy the Kid - Shoe
I know the forum is fairly much an advertisement, but some of the pics of exploded pressure tanks are quite convincing! I read a few testimonials on other sites from folks who used them, but i also found a dearth of information as to HOW they work. FM's post about overheating makes it appear the pump just works against an artificial head, in which case i see no advantage to the pump, except it doesn't turn on and off as much perhaps. My best bet isapparently to get groovy with the sprinkler allotments. I bought some to try, but i think some are variable, so that may be the way to go since my system is already installed and actually sized for a smaller output than this pump at this level will produce.Considering the head i'm pushing against with my own head in learning about the vagaries of just one well, i'm awfully glad i don't have even two to consolidate, let alone a field of them!
I know that large centrifical pumps used for water distribution they monitor the temperatures. You you run them for a long time with too little flow they heat the water into steam and then burn out the bearings.But to keep from getting water hammer. They start them into a closed valve and then slow open them.Also they do that because they are often starting into pipes with high pressure and you don't want to try and fight back flow as the motor tries to get upto speed..
William the Geezer, the sequel to Billy the Kid - Shoe
Yes, i read the cycle stop valves would do away with hammer. My old well produced a bit of sand that i probably could have lived with using Jacuzzi's Sand Handler pump, but the filter i had would plug shut in just a couple cycles of the irrigation valves (Orbits operated with a solenoid - those green, plastic ones), when the hammer would just make the well dump sand into the line. I've seen one pump that was completely filled with sand...didn't look like fun to clean out.I was smacking myself in the head wondering if a cycle stop valve would have decreased the hammering of the irrigation valves enough not to have to deepen the well. Too late now...
Edited 6/3/2009 10:10 pm by splintergroupie
Cycle Stop Valve vs Axial Flow Pumps
"They start them into a closed valve and then slow open them."
"Also they do that because they are often starting into pipes with high pressure and you don't want to try and fight back flow as the motor tries to get upto speed."
I disagree doing this with an axial flow pump.
The above quoted statements are true for Radial Flow pumps ONLY.
Submersible Pumps are based on axial flow due to the constraint of the well bore.
An AxialFlow Pump does not "unload" when the discharge port is closed or significantly reduced, just the opposite of a Radial Flow Pump. An Axial Flow Pump sees the greatest load on startup.
Introducing a Back Pressure increasing device will cause the power required to increase while reducing the flow.
Yes I can force my SubDrive 75 to only produce 2.5 GPM, for my GEO Heatpump, if I add apporximately 130 pound increase of back pressure. The pump will require all 1-1/2 HP to operate under those conditions. But the pump will produce low flows if the frequency is reduced via a VFD, and do so at a greatly reduced power load.
But the SubDrive 75 has its Achilles Heel when operated at low flow for extended periods such as the GEO presents. The sensor switch and the pump checkvalve both suffer from repeated excursions. The switch is an easily replaced item; having to pull the pump for the check valve is costly. And the failed check valve causes "backspin" on shutdown; if the controller tries to restart the flow during backspin, significant damaging operational conditions can occur and destroy the motor os the controller. Spoken from experience!
.
I expect the pump to run several hours a night, or every couple nights, so it appears my best bet is just to get really accurate with adjusting the sprinkler heads, since i have only about 15 gpm to work with. I was thinking that constant pressure at the sprinkler heads would make their "throw" more accurate, too, but it's not that big a deal. I wasn't aware that the pump could overheat, but it's as you speculate, a 4" pump in a 6" casing. Mostly i was looking to go even easier on the pump, but i guess it's not that simple. The last thing i want is to pull the pump to install a sleeve. I'm shocking the well as we speak for iron bacteria introduced with the operations here last week.
Hi again SG,
I was away from the computer for several days and couldn't respond to your note.
I read through some of the "forum" (read propaganda) from Cycle Stop and I felt like they were selling the cure for world hunger. Cycle Stop valves work in some situations, but attacking VFD technology in favor of their product is kinda lame.
A cycle stop valve works by creating artificial head against the pump. The heat I mentioned is not generated by the pump, but rather the electric motor driving the pump. Yes, it is in water but it relies on that water flowing past it to cool it. In the case of a flow restriction, water is not flowing past fast enough to provide adequate cooling. This is where the cooling sleeve comes in. By installing a 4 inch pump and motor in a 4 inch cooling sleeve, the velocity of the water is increased so that even in low flow conditions, the motor remains cool.
I am not a water well driller, but when we had clients complaining of a sand producing well, we always went to one of two possiblities and it applied 90 percent of the time.
-Broken well casing allowing gravel pack and sand in the well.
-Overpumping of the well.
I would say that a visit with your favorite local well driller would be the best bet if there are sand problems with your well. Sand production from a well-constructed modern well is a symptom of a larger problem in most cases.
Hope this doesn't add too much confusion.
Frank
I had sand from the beginning in my "old" well, and nothing broken. This is the bottom of old Glacial Lake Missoula that filled and flooded a few times while collecting volcanic dust and glacial debris, too. When we deepened the well, we even brought up bits of old wood from trees that got captured in the glaciers. Unfortunately, i have bigger problems now than ever before: my well's now contaminated with iron bacteria. I can't say if the drillers brought it in or it's home-grown, but i've shocked the well, let it run for a few days, no improvement and pressure is way down, so i'll shock it again tomorrow. I went from the nuisance of sand to the nightmare of this bacterial contamination and orange water. Damn...it was pristine and lots of it when the guys left last Friday. I thought my water woes were done with, but they've apparently only started.I'm considering grouting the well to seal off the perfs in the pipe at the present contaminated level, then using the extended length of the casing as a sink for sand to fall into, and re-perf the pipe at the former level. The pump could still hang at about 240' or so. Any thoughts on that? I have a feeling i'm traveling solo now...not a long of cutting-edge technology where i live.
http://www.pumping.com.au/biostat.html
Not sure if such a system would be applicable for you. Sounds like a volume of the pellets get wetted to make solution and then free-drain afterwards. In a freezing climate this may be a big problem. Or maybe not.
Alternate solutions would include dry-pellet cholrinator which is what we've used here for 15 years against iron bacteria. It does the deed nicely for us, but the resulting ferric iron has to be removed with a sand filter before the water hits the softener. Failure to do so will slug a conventional softener in relatively short order.
Edited 6/7/2009 8:58 am ET by HootOwl
Thanks for the link, but all our stuff had to be buried 6' deep. (Yeah, digging up the pitless - twice - was fun!) I've read about the pellet-chlorinator, then all the other stuff you have to do to the water. I'll have to make some decisions about which way to go is more reliable...esp since our rural power isn't reliable itself. I've had the pump running non-stop since i discovered the problem, with shocking a few days ago. I'm going to shock it again tomorrow, and hopefully see more improvement. It's much improved, but not fixed yet. I hope the pump doesn't disintegrate in all the chlorine........
but all our stuff had to be buried 6' deep. (Yeah, digging up the pitless - twice - was fun!)
???? Why not just dig a bit more, form up and pour a wellpit ? Seems easier to me than having everything buried and requiring all that digging everytime something needs servicing. Would also allow you to mount that water treatment equipment below frost/freeze level.
Our pitless adapter is actually down in a pit, the well-casing extended upwards to above grade and then the dry-pellet chlorinator could be mounted above grade rather than down in the pit. (Easier to keep an eye on things that way, swap out pellet bottles when needed, etc. And because the dry-pellet machines can be mounted even where/when sub-zero temps are present.)
You say that your 'pressure' is now reduced. Do you mean the actual pressure that the pump can achieve/deliver or just the volume output of well (gpm)? In either case this could be the result of a pump screen that's now clogged with flocks of IA....or other 'stuff'. Screens clogged with IA is somewhat common problem when there's a high population of IA present. You've probably already realized the above, but thought I would mention it just in case.
Edited 6/8/2009 9:53 am ET by HootOwl
Some folks use pump houses, some have well pits, but the trend is to pitless around here, for weather and bec it's easier to monitor the controls from indoors. I think it's just a weather-related issue. I've heard of stuff freezing up in a well house or even a well pit - we had -19º here last winter and it's been -30º several times since i've lived here. Snow melt can fill up a well pit pretty quickly, too; a bunch of neighbors got flooded out and lost their controls (and water supply for a while) after the Great Snows of '98 followed by the Great Rains of '99. Now there's a mess to clean up! I sailed through that stuff, lol....Can you give me more info on your chlorinator? The idea of chlorination is anathema to my earth-mama mind-set, and the effect on my greenhouse and eventual landscaping concerns me. What kind of chlorinator, what problems have you had, and what sort/size of filter do you use to take out the precipitate? Heck...i'm going to start a new thread on iron bacteria....could you answer there instead?
One way to extend pump life is bigger pressure tank(s) which reduce cycling on and off. You can add additional tanks in parallel with your existing one. I'm currently running one with 15 gallon draw-down plus one with 40.
Scott.
I'm also considering a larger or in-parallel tank, though i did some creative DWV plumbing in the utility based on the size of this one. Might have to wait for an in-flow of the dollar river...this little deal came in at "only" $5500, when i'd figured at $7K, bec those boys like me, by golly...and no doubt bec this is the fifth well we've played with together.
I worked on a cycle stop valve last week.
It was in a garage and supplied water for sprinklers around an appartment building.
Where the two halves joined together it had started to spray water.
I was able to use a bar clamp to disassemble it, clean and lubricate it, it went together fine and didn't leak. It had only been in the system about four years and the system is only used about four months a year.
Just saying you might run into some maintenence issues that a larger tank may not have.
That's the kind of real-world experience i was looking for. I expect an apartment building has pressure in excess of mine at 60 PSI, but still...that'd be a lousy headache to come home to anytime.You've been giving me quite and education with every plumbing issue i put up. Thanks very much for the repeated advice.
I am sorry to be bringing up and old post, but I just know found it. Not trying to advertise here either, just wanting to get the facts straight.
“I sold several of the Cycle Stop valves. In general, they work as advertised.”
“If you are using your system for long term irrigation, they are not very efficient. We referred the them as a poor man's VFD (variable frequency drive).”
“Cycle Stop valves work in some situations, but attacking VFD technology in favor of their product is kinda lame.”
CSV’s do work as advertised, yet most people, including many who install them, do not know how they work. They won’t help much with iron bacteria or sand, but a CSV is not the poor man’s VFD, they are the smart man’s replacement for VFD’s. CSV’s were designed to replace VFD’s and have been doing so since 1993.
There is a lot of myth-information about VFD’s. VFD’s are not new and they do not save energy. A CSV is superior to a VFD in many ways. A CSV can be just as efficient as a VFD. CSV’s lengthen the life of pumps and motors, VFD’s shorten the life of pumps and motors.
VFD and pump manufacuers are making a killing on the myths people believe about VFD’s. If you want to know what is best for the end user, just do the opposite of what the pump and VFD manufacturers advise.
So explain how
I get really skeptical about "magic" wonder devices.
Apparently I am not allowed to post a link to a graphic of how it works. There is nothing magic about it, just a simple valve with a common sense approach to pump control. I can understand skepticism. I was skeptical myself. That just made me want to figure out how it works. If people didn’t check into things they were skeptical about, we wouldn’t know man could fly and we would still think the earth is flat.
Nothing stopping you from posting a link. You can't inline a graphic via a link, but that shouldn't hinder you much.
Valve-
Copy to file the graphic you wish to post. Stick it on your desktop (or wherever you can find it). Use the ATTACH FILES TO THIS COMMENT box below your reply to get it on the board.
It is an interactive graphic, so I think all I can do is post the link. I will try it again. Here is the link.
http://www.cyclestopvalves.com/simple/home.php
That will only work with a pump that can be throttled. And it's not a given that the current draw of the pump will go down as flow is reduced. Seems like you still may need to have a special pump.
The only pumps that can't be throttled are positive displacment pumps, which are rare to see in the water industry. Regualr Jet pumps, submersibles, turbines, centrifugal pumps, can all be used with a CSV. Some of these pumps will reduce in current better than others when throttled, but as long as the amps drop at least a little, it will work with a CSV. No special pump needed. But the pumps that draw the least current when throttled work best.
This can save power, only if the wrong pump was installed.
The only way I see this being able to save power would be if the pump, as installed, is running off the curve on the high side, far enough to be losing efficiency.
Then the increased head could push the pump back into a more efficient flow regime for the pump.
If the pump is properly sized for the hydraulics of the well and discharge system, increasing the head will cut efficiency.
From experiences dealing with some well equiping contractors, it is probable that the pump could be the wrong selection for the conditions. But my experience is that they are almost as likely to be undersized, and the valve will make them less efficient.
Valveman is right in that as you throttle a centrifugal pump it TENDS to actually cause rotor speed to increase and as a result lower current draw. But fluid dynamics is a complicated beast, and, in addition, the motor depends on water flow for cooling, so there are lots of caveats.
I never said it was more efficient. Just that the amps drop as the flow rate is throttled. There is nothing more efficient than a pump running at its best efficiency point. However a CSV will allow you to install as large a pump as you might possibly ever need with a small pressure tank, and still be able to safely use it like a small pump when needed.
Yes submersible motors need a certain flow rate to stay cool. But when the amps are reduced by as little as 25% from throttling the pump, the motor is de-rated enough to be able to safely pump 140 degree water. So it takes very little, less than 1 GPM flow of cool water, to keep a submersible motor from overheating when it is de-rated from being throttled back.
Another way to vary the flow rate of a pump is to use a Variable Speed or Variable Frequency Drive. These will reduce the amp draw of a pump as well, but do not save energy. They also do not de-rate a motor, they create a smaller motor from a larger one. So the motor still has to be cooled like it is a fully loaded motor. A motor can’t safely get to as low a flow rate with a VFD as it can with a CSV.
How is it possible that a variable frequency drive can reduce the current flow through a motor without reducing the power used???
"How is it possible that a
"How is it possible that a variable frequency drive can reduce the current flow through a motor without reducing the power used???"
VFD’s are expensive, short lived, and greatly decrease the life expectancy of pumps and motors. Motor, and VFD manufacturers just love the fact that most people wrongly believe reducing the current by varying the pump speed will "save energy". This way the end user is tricked into believing VFD’s are worth the added expense, technical problems, and short life of pumps, motors, and the VFD itself.
In reality reducing the pump speed with a VFD drastically increases the energy used per gallon produced. One reason is that a centrifugal impeller loses head by the square of the speed. So you can’t reduce the pump speed by more than about 10%, which only reduces power consumption by 27%, and still produce enough head to get water to the top of the well or build the pressure required by the system. There is certainly no way to reduce the speed by 50%, which would reduce the power used by 87.5% as claimed by many VFD salespersons.
The reduction in current from a VFD is also not linear to the reduction in flow. For instance a 10 HP, 100 GPM produces 10 GPM per horsepower. Slowed with a VFD until the motor is only pulling a 5 HP load makes it look like you are saving 50% in energy. However, the 10 HP pump slowed to a 5 HP draw is only producing about 10 GPM total. That is only 2 GPM per horsepower, which means a VFD actually increases the energy used per gallon by 500%.
"VFD’s are expensive,
"VFD’s are expensive, short lived, and greatly decrease the life expectancy of pumps and motors."
None of these statements are true.
I would not consider using variable flow in a residential water system. That conversation is beside the point. The OP was about protecting a submersible well pump, that is connected to a large presure tank and in a single family residence. Unless the pump is oversized, the system is in no need of modifications or changes.
As far as VFDs are concerned, in the commercial HVAC world, their use in variable air flow and variable water flow systems is well documented in terms of longevity and energy efficiency. No engineer considers "energy used per gallon" as a credible or useful parameter. The fact is, loads vary. Load matching in air and water systems saves energy. Pumps and fans are not negatively impacted in variable speed applications. What is the supposed degradation mechanism you claim?
Those that understand heat transfer and/or psychrometrics further realize the benefits of variable flow systems.
Proper sizing and application, use of high efficiency motors and establishing practical commissioning and operational limits precludes any motor degradation as well.
I do not have experience using VFDs on domestic water systems. Misapplication by idiots notwithstanding, your statemnts are incorrect.
"I would not consider using
"I would not consider using variable flow in a residential water system. That conversation is beside the point. The OP was about protecting a submersible well pump, that is connected to a large presure tank and in a single family residence. Unless the pump is oversized, the system is in no need of modifications or changes."
That conversation "is the point" of the OP. The same companies who are pushing VFD’s in commercial application are now pushing them as the greatest thing for residential water systems as well. But that is because they make a lot of money on VFD’s that cost a lot and don’t last very long, not because they save energy as over zealous sales persons say. All residential pumps are oversized. They are sized to the peak demand of the residence, even though the water is used at much less than peak demand most of the time. So variable flow pump systems are just as beneficial for a residence as they are for commercial applications. That is as long as they are dependable and long lasting which is contrary to a VFD installation.
"As far as VFDs are concerned, in the commercial HVAC world, their use in variable air flow and variable water flow systems is well documented in terms of longevity and energy efficiency."
You should go back and read the fine print in the articles that "document" such things. You will find that the load was reduced, the pressure required was lowered, a smaller pump or fan was installed, a bleed or dump valve was taken out of service, or something else was changed that was responsible for the energy reduction, but the addition of a VFD wrongly gets all the credit.
"No engineer considers "energy used per gallon" as a credible or useful parameter."
Some of them are smart enough to know that the amount of gallons produced is the actual work done for the energy used. The ones that don’t understand this should not be calling themselves engineers.
"The fact is, loads vary. Load matching in air and water systems saves energy. Pumps and fans are not negatively impacted in variable speed applications. What is the supposed degradation mechanism you claim?"
Sure load matching saves energy if that means properly sizing a pump/motor to the load. Reducing the speed of an oversized pump/motor increases the energy used when compared to using a properly sized motor. All pumps and motors are negatively impacted by variable speed operation. A short list of the problems created by VFD’s include Harmonics, voltage spikes, reflective waves, resonance frequency vibration, bearing currents, lack of cooling, etc.
"Proper sizing and application, use of high efficiency motors and establishing practical commissioning and operational limits precludes any motor degradation as well."
So you do understand some of the problems of VFD control! High efficiency motors help, but also had to be changed from 600 volt to 2KV insulation to better withstand the 2,000 volt spikes from a 480 volt VFD. Auxiliary fans and/or air conditioned mechanical rooms help cool the electronics and motors whose fans are spinning too slow to be effective. Air filters help keep dust and lint out of the electronics. Additional electrical grounding as well as line and load reactors help reduce harmonics. Grounded rotors and/or insulated bearings help reduce EDM damage to ball bearings caused by VFD bearing currents. Locking out critical speeds helps reduce resonance vibration. Limiting the minimum speed helps reduce pump deadheading.
"I do not have experience using VFDs on domestic water systems. Misapplication by idiots notwithstanding, your statemnts are incorrect."
There are a few good applications for VFD’s. However, I find that they are most useful to tune systems where proper engineering practices are not understood or followed. I won’t go so far as to call them "idiots", but many VFD’s are Myth-applied by those who should know better.
I'm not basing this on something I read
So I can't "check the fine print". I have designed and installed variable flow systems in new buildings and retrofit applications dozens of times. I didn't just read about, I did it and the results are real.
"The same companies who are pushing VFD’s in commercial application are now pushing them as the greatest thing for residential water systems as well." Such as? The manufacturers that I am most familar with (Danfoss, Yaskawa, ABB) do nothing of the sort.
Your background seems to be in domestic water valve sales, not engineering.
Variable primary flow, high dT water systems coupled with mod-con boilers and variable capacity screw or centifugal chillers are state of the art and practically the only way to acheive significant energy savings over ASHRAE 90.1 standards (this is a key component of LEED certification). These types of system are possible only with VFD controlled high efficiency motors and modern mircoprocessor based equipment controls.
Without wasting extensive amounts of energy in reheat energy, the only way to effectively dehumidify in off peak load conditions in the cooling season is by utilizing a variable air flow system. Fan energy savings are very significant in a VFD controlled system, as compared to constant volume system. Not " or something else was changed that was responsible for the energy reduction, but the addition of a VFD wrongly gets all the credit." VFDs may occassionally be used to overcome poor design, but that is not how they regularly and consistently applied in the commercial HVAC world.
Lets talks some details here: "A short list of the problems created by VFD’s include Harmonics, voltage spikes, reflective waves, resonance frequency vibration, bearing currents, lack of cooling, etc."
harmonics - all rotating equipment has critical harmonics. Basic startup and commisioning of a variable flow system includes identifying and avoiding operating points that are at critical frequncies. So this is not a real problem except when incompetence is involved.
voltage spikes - this is a new one for me.
reflective waves - sounds like complete BS to me, but I'll listen to some more details
stray voltage and related bearing damage, in reality of minimal consequence, is readily addressed with proper grounding, which is common accepted practice.
lack of cooling - 10% BEP for centrifugal pumps is maintaned in every designed system I have ever seen. I'm sure there are some examples where this isn't maintained, but bad design is not the fault of the components. 30% of design air flow in VAV system is also a common minumum and provides adequate cooling for all but the cheapest ODP and TEFC motors, which have no place in a VAV system or VFD application of any sort. In some industrial applications where turn-downs are expected to be greater than 10:1, low speed VFD rated motors are appropriate.
" but also had to be changed from 600 volt to 2KV insulation to better withstand the 2,000 volt spikes from a 480 volt VFD" Any verifiable source for this claim?
What you list as "problems of VFD control" are standard, common design considerations that any competent engineer would address. And yes, I fully undersand them all.
"I find that they are most useful to tune systems where proper engineering practices are not understood or followed." You seem to have more experience "where proper engineering practices are not understood" than I. Possibly the source of our diagreement.
I said there are some good applications for VFD’s, and HVAC maybe one of them. However, this thread was about well pumps, which I believe are not a good application for VFD’s. High static loads greatly limit any possible reduction in RPM. Long wires to the bottom of a well or to any pump have a “reflective wave” which increases the voltage spikes to the motor. The switch to 2,000 volt motor insulation happened about 20 years ago as a first attempt to mitigate problems from VFD’s. You can ask your motor company about it if they have anyone old enough to remember. There are so many side effects of VFD control that there are entire companies and forums dedicated to mitigating these problems. Once someone has a drink of the VFD Cool Aid, discussing these things is like telling a six year old there is no Santa. They don’t want to believe you, and they are devastated when they realize you are right.
Well pumps
" This thread was about well pumps, which I believe are not a good application for VFD’s"
I agree, as was my opening statement.
Also, as was previously stated, not only are VFDs inappropriate in a residential domestic water application, so are the magic valves you prefer over VFDs. These are simple systems, and if setup properly (without VFDs or magic valves), work for decades very reliably. The work involved with pumping water out of the ground is not affected by reducing flow to meet demand. GPM x dP. If the excess work is stored in a bladder type expansion tank, it is not lost and available as necessary. If you use 100 gallons a day and you have to overcome 150 feet to do so, you will use a given amount of energy. This is unaffeted in any significant way whether that 100 gallon usage occurs over 10 hours or 1. This assumes a working check valve at the inlet to the pressure tank.
Regardless of the applicability of VFDs for well pumps, most of the statements you made concening VFDs in general were not application specific. They were incorrect and were misrepresentations of common, acceptable practices, justify at best by comparison to poor/incompetent installation or design.
I have no dog in this fight. I know my industry very well. I know from 20 years of experience that every product can be made to look inferior in poor applications and/or poorly designed installations. Ususally, this is due to salesmen that enough enough technical jargon to appear knowledgeable but are not.
You magic valves can easily knock down the VFD strawman you created. Now thats drinking the KoolAid.
Yeah, the web site was relatively useless -- no actual information. Such sites do not give me a warm feeling about a product.
I can always tell how much someone knows about pump systems by their reaction to our web page. Engineers and others who really understand pump systems and all the problems that go with VFD’s, tell me our web page is wonderful. They enjoy and learn a lot from the numerous references, articles, and explanations.
When someone says they didn’t get any “useful information” from our web page, it is a sure sign they understand very little about pump systems. Not knowing that cycling has always been the biggest problem with pump systems of all types and sizes is another red flag. Not knowing the “manufacturers you are most familiar with, Danfoss, Yaskawa, and ABB” are heavily promoting VFD’s as the answer for every type and size of pump system, is further proof that you are talking about things you know nothing about. Danfoss is big into controlling pump systems. Their sister company Flomatic, even makes a “copy cat” version of the Cycle Stop Valve. Yaskawa, which is really the third remake of the old Rediflo 1 and 2, is across the isle from me at every water well trade show. ABB actually makes a private label version for Goulds called the Aquavar, and another for Pentair called the Pentek Drive. In the water pump or water well industry, promoting VFD’s is all about making money.
You apparently do have a “dog in this fight”. Although it is obvious that you are the “salesman that knows enough technical jargon to appear knowledgeable, but is not”. I have over 40 years experience in the pump industry and an education in electronics. I stopped using VFD’s about 20 years ago, probably before you even got out of school. You are talking out the side of your mouth about a product that is well proven and has been replacing VFD’s for almost 20 years. I would be happy to try and help you understand “common, acceptable engineering practices” to keep you from looking so foolish. There is nothing magical about the “valve”. It is just a matter of really understanding pumps that will give you the warm and fuzzy feeling. A closed mind is a certain mind, which is why you are so certain. But I understand it is hard to “un-drink the Koolaid”.
Your web site didn't do anything for me either. I suppose the purpose of the valve is to stop short cycling, but there is no real explanation of they do. I can't see a purpose in throttling the output of a pump into a storage tank. If short cycling is a problem, you need a larger tank.
I too have experience with VFD drives and some of your criticims are nothing I have seen in them. We use VFD to control pumps in clean room applications where the pump must run continuously, but provide variable flow rates. We only experience occasional pump head failures, but no motor problems to speak of.
I just went back to the site and looked again. Very little in the way of technical info, lots of (rather cheesy) "flash" (so to speak). You try to cover it up with "righteous" indignation, but that doesn't do it here.
Since you apparently understand how these cycle stop valves work, would you mind taking a crack at explaining it?
I'm not trying to give you a hard time - Just trying to learn something.
It's basically nothing more than a pressure-limiting valve, similar to what would be used to limit pressure coming into a house from a main. Details are likely different, of course, primarily in that you want the CSV to be a hair "leaky" whereas that's bad for your standard pressure-limiting valve.
The valve is placed between pump and pressure switch/tank and "throttles" flow from the pump to roughly match demand. Thus, so long as there is some demand, the tank never refills, the pressure switch never reaches set point, and the pump, in theory, never shuts off.
When you throttle a centrifugal pump you curiously tend to reduce current draw (for most conventional designs), so there is some reduction in instantaneous power demand. However, since the pump is spending more energy generating turbulence vs pumping water (and must pump for a longer period of time), the KWH per gallon likely goes up, compared to a reasonably balanced conventional tank system.
Non-technical background,
longtime sales man. I understand. Education in electronics? I take that to mean High School diploma, failed out of trade school.
IF your product was a good as you say, you wouldn't have to "bash" the competition to hock your wares. Red flag immediately.
BTW, your product is warranted for a mere 12 months. Most VFDs come with a factory parts and labor warranty of 24 or 36 months. So much for the dependability argument. The "unreliable" competition stands behinds their product three times as long as you stand behind yours.....hmmm. Makes you think.
When a company's website is mostly a parroted sales pitch with no credible trade or engineering references, that raises a flag of suspicion. A red one.
When someone like you gets their hackles up and can provide no real technical justification for any of your standard talking points, that raises another flag. A big red one.
I really like the sophmoric revision to the Grundfor letter. Childish. You morons should have know better than to actually publish the real letter, too. It explains, in pretty good technical detail, that your snake oil sales pitch is based on a lack of understanding of pump operation and affinity laws. Good job. You idiots even stole the pump curves (Fig 1and Fig 2) and used them incorrectly in closest attempt at a technical description of pump operation on the website!
I'm sure the individual that invented and patented these valves is an intelligent fellow with a lot of knowledge about well based large irrigation systems. You're not that guy.
Sales pitch and insults. Even you website can't even site A SINGLE TRADE REFERENCE. No industry acceptance, its all smoke and mirrors. You do post a lot of personal attacks on professionals article published that point out the physics that makes you FOS. Are there any trade journals or publications you can reference in 40 YEARS of experience? Anything that not's hand written or made-up. While the folksy touch might play well in Lubbock, it doesn't lend any credance to your argument. Surely, other Ireally smart people have realized the wonder of the CSV and sought to enlighten world? No?
Waterhammer, for those of us that know more about hydraulics than to repeat "myth" over and over again, is a very simple problem to solve. Do you know how?
But...I'll give you some rope: Give me a numerical example of a real energy consumption anyalsis of CSV versus a VFD on the same pump, that makes your point. Include water flow rates, head, pump speed and energy consumption at the points of comparison. Make your point now or go away.
There are a lot of technically knowledgable folks here. Make a technically competent argument. If it holds water, we'll let you know. So far in this regard you FAIL.
Flusterated
We have him so confused now, he can't tell you from me!
All that technical information is on our web page. You apparently just don’t understand what you are reading.
KW and PF comparison;
http://www.cyclestopvalves.com/vfd-energy_13.html
Pump Curve comparison;
http://www.cyclestopvalves.com/csvtechinfo_15.html
An article from the Water Well Journal by a reputable and enlightened Engineer.
http://www.cyclestopvalves.com/pdf/csvapplications_10.pdf
Another article from Engineers who understand;
http://www.cyclestopvalves.com/pdf/csv-vs-vfd_16.pdf
Here is a study from a USDA Engineer;
http://www.cyclestopvalves.com/letterseditor_25.html
And there are lots more, if you know what you are reading. I have at least three times the hours of other EE’s, and years more experience in the real world. But I have probably forgotten more than many people will ever know on this subject.
Since most of the valves we sold 15 to 18 years ago are still working, warranty has never been an issue. Anyone who knows us understands we are a reputable company and would never hold anyone to 12 months warranty. We would warranty a 10 year old valve if it was defective or failed to work as advertised. Our only failures come from freezing, pumping excessive sand or other debris, which is not a product failure or a warranty situation.
I didn’t start the name-calling. I am just defending myself. But I do get my “hackles” up when someone acts like they know about pump systems, yet it is obvious they don’t have a clue. I think you need research how to read a pump curve. I assure you that Grundfos doesn’t think my rebuttal to their article is “childish or sophomoric”. They and several other manufacturers have been wishing I would go away for almost 20 years. If they could prove anything I say was not correct, we would have been facing each other in court years ago. I think it is up to you to prove I am incorrect. If you can prove you know more than USDA or NASA Engineers then show the math, or you should go away and stop making yourself look foolish.
Adding a larger pressure tank, soft starting a pump, or slow opening a valve has always been the answer to water hammer from engineers who “think” they understand hydraulics. Then someone who really knows has to get a change order to fix it.
You need to make a technically competent argument. If it holds water I will let you know. I think it is funny when the kid in the back of the class with the lowest grade point thinks he can tell anyone they failed. But I would still be happy to be your tutor if you ever want to expand your mind instead of your ego.