"Misinformation"

[Cary Austin]

Since Cycle Stop Valves began in 1993 we have received many letters and emails similar to the ones below.  These are the typical things a Pump Service Company thinks and says when they do not understand the effects CSV’s and/or VFD’s have on pumps.

From a Pump Service Company
Lanse in CA

Your misinformation about VFD's is ridiculous. You say you haven't used them in 20 years. Well, are you still using the same computer you had, if you even are up to that point, 20 years ago?
I use VFD's when appropriate, also the Grundfos CU301,  and standard pumps when indicated.
Your valves DO NOT save energy. They do reduce cycling which is good for the motor life and reduce power consumption due to starting load, but that is offset by longer run times. Proper sizing of pumps is more important.
When the system has circuits that have widely varying demands, a VFD is indicated. You claim they don' save money. Well, look at the facts. A pump running at half speed pumps approximately one half the amount of water, yet consumes only about one tenth the power consumed at full power.
Your valves were all we had long ago, but dinosaurs are gone. Stop spreading misinformation.
I dare you to post this opposing comment.
Lanse
Pump Service (since 1984)

[Cary Austin]

Hi Lanse
I will be happy to post your comments on our web page.  I will post them on the forum, which will give you the opportunity to reply and apologize for your lack of understanding on how pumps work.

It would have helped for you to show a pump curve or give some kind of basis for your incorrect assumptions.  I have plenty of pump curves and proof posted on my web page for you to study.

“Proper sizing of pumps is more important” is the only thing you said that was factual.  You can go to my other articles and look at pump curves to see the math that proves everything I say.  But I will give you a little overview here as well.

Well, as you said, lets “look at the facts”.  If you knew how to read a pump curve it would be obvious there is no way for a “properly sized pump” to be slowed down by 50% and draw only 10% as much energy.

When using a VFD, head is lost by the square of the pump speed.  The pump must always spin fast enough to lift the water to the top of the well or building, and still produce 50 PSI on top of that.  Maintaining this certain amount of head greatly limits the minimum speed the pump can spin and still push water out the faucets. 

There is no way this static head could ever be reduced by 50%.  Even if you could reduce the head by 20%, because head is lost by the square of the speed, a 10% reduction in pump speed is the most the pump could be slowed down.  Even though energy required is reduced by the cube of the pump speed, a 10% reduction in speed only reduces the energy consumption by about 28%, not 90% as you suggested.

Now even though the Affinity Law shows a 10% reduction in pump speed creates a 28% reduction in energy use, the actual energy required will still be regulated by the amount of water being used.  In other words even though the pump still has to spin at 90% of full speed to produce the head or pressure required, which would only decrease the energy consumption by 28%, the actual energy used can still be reduced to about 50% of full load.  This is because when the pump is at it minimum speed, the horsepower curve still moves to the left as the flow rate is restricted and moves to the left, which is how a pump works normally.

When slowing a 1HP pump/motor to its minimum possible speed of 90%, restricting the flow to 1 GPM will still require ½ HP energy. This means a 1HP pump that can produce 10 GPM at the design point will only drop to about 1/2HP load when slowed down with a VFD to produce 1 GPM.  Producing 10 GPM with 1HP is 10 GPM per horsepower.  Producing only 1 GPM while still using 1/2HP energy means the VFD is using 500% more energy per gallon.

I know this is confusing for those who do not know how to read a pump curve.  Pump and VFD manufactures are using this confusion to make you think a VFD can save energy.  This way they con you into buying the most expensive, least reliable product, because VFD’s are very profitable for the manufacturers.

“The VFD makes the amps go down by 90% and saves 90% in energy costs.” Yeah right! They don’t want you to pay any attention to the flow meter “behind the curtain” that shows only a 50% amp drop that only happens when the flow is reduced by 90%.  Then you would understand that anytime you reduce the pump speed with a VFD the energy used per gallon increases dramatically like 500% or so.

Why are you letting the pump/motor and VFD manufacturers keep you in the dark? Look at the flow meter and learn how to read a pump curve.  Then learn how to read a multi-rpm pump curve and you will discover the error in your thinking.

Cycle Stop Valves are actually much newer than VFD’s.  I had been through Electrical Engineering, built computers, and had lots of experience with VFD’s many years before you started working with pumps in 1984.  I would never subject any of my customers to all the problems and expense of a VFD. 

Even though I haven’t installed a VFD for anyone since about 1991, I still play with the news ones that come out every 18 months or so.  I try to keep up to see if anybody ever figures out how to change the laws of physics.  In the 25+ years I have been dealing with VFD’s they have gotten smaller, lighter, faster, and cheaper.  But no one will ever be able to change the laws of physics.   So no one will ever be able to make them save energy, make pumps last longer, eliminate harmonics, voltage spikes, bearing currents, and all the other negative side effects that are naturally inherent with VFD’s. 

There are still LOTS of dinosaurs alive today.  Dinosaurs are the ones still using VFD’s. CSV’s are much better and a much more modern way of getting pumps to do the multiple jobs you need them to do.

There are about 40 more articles with pump curves that you can read at these two links.

http://www.cyclestopvalves.com/vfd-energy.html

http://www.cyclestopvalves.com/csv-vs-vfd.html

Ask yourself why in all these years, none of the pump, motor, or VFD manufacturers have taken me to court and tried to shut me down for the things I say?  It is because anyone who understands pump curves and VFD’s knows I am telling the truth.  I would not be able to say, “VFD’s for centrifugal type pumps are a scam” if it were not true.

I will take it one step further and say that anyone who sells VFD’s for these types of applications is either a “scam artist”, or completely ignorant of how pumps work.

If you can show proof that ANYTHING I say is incorrect, please post it here.  This is not my first rodeo.  I have had this argument with some of the top engineers for the major pump companies over decades.  If you will notice they never come back to argue with the facts that I present.

Example;  http://www.cyclestopvalves.com/pdf/pumpman_3.pdf
 
Some of my best friends and customers started out accusing me like you did.   I hope you and I will become friends and you will start asking some intelligent questions.  But you can’t just call me a “Dinosaur”, “ridiculous”, say nana nana boo boo, and tell me to stop “spreading misinformation”. 

If you want to prove what you are saying post a curve of a pump that will produce the head required at 50% of speed and only use 10% energy.  When you realize that is not possible, I will be here to answer your questions.  It is the pump and VFD companies that are lying to you, not me.
Thanks
Cary

[Cary Austin]

Another email from;
Lanse
Pump Service (since 1984)

Cary,
Your arrogant reply shows that you don't understand. In a perfect world of having a pump deliver at a set constant pressure and output, neither a VFD nor a restrictor, which is what your valves are, would be needed. A VFD allows a pump to deliver a widely varying demand at a constant pressure.
I can see that further discussion with you it fruitless; keep your opinion and I'll keep mine.

[Cary Austin]

I can tell Lanse believes his story, as he is sticking to it no matter what the facts say.  I have had this same argument with easily more than 100 other pump installers and engineers over the last 20+ years.  I usually try to educate them over private conversations.  I only posted this one because Lanse dared me and because I am tired of getting so many accusatory emails.  I also wanted others to see the hatred I experience for having to tell so-called “professionals” that VFD’s cannot save energy.

In Lanse’s defense he is only repeating what he has been told by his pump suppliers and manufacturers.  I am sure he has spent many hours in “classes” being brainwashed by VFD and pump salespeople.  The alligator told the frog to “trust him, and not to worry”. He would gladly “take the frog to the other side of the pond”?  The frog realized only too late that the alligator (VFD salesperson) had an ulterior motive. 

Lanse said “…..”
“I can see that further discussion with you is fruitless;” Further discussion??  You have not tried to discuss anything.  All you did was make some incorrect statements about VFD’s saving energy, running at 50% speed, and being able to work at 10% of the power required.  Then after accusing me of being “arrogant, ridiculous, not understanding, spreading misinformation, and selling dinosaurs”. You dared me to post “your opposing comments”, which I did.  Yet you still cannot show proof anything I said was incorrect.

“In a perfect world of having a pump deliver at a set constant pressure and output, neither a VFD nor a restrictor, which is what your valves are, would be needed.”
It is far from a perfect world.  The demand, and therefore the output of the pump as well will vary widely on almost all pump systems.

“A VFD allows a pump to deliver widely varying demand at a constant pressure.” This is just further proof that you still do not understand. The CSV maintains a constant pressure as well, and allows even wider variation in demand than a VFD.

I know it is hard when you realize everything you thought you knew about pumps since 1984 or whenever, is completely wrong.  I went through the same thing myself.  I had been working with pumps for 20+ years and thought I knew everything.  Then one day when playing with a pump system that had both a Valve and a VFD I had a “eureka moment”.  After that I have spent the last 20+ years re-learning everything.  Only when you finally admit you don’t know all there is to know can you really begin your education.

Explaining to some people that VFD’s do not save energy is like having to tell kids there really is no Santa Claus.  Some finally believe, others will deny the truth until the end of days.  Either way most will hate me for having ruined their little fantasy.

In the last 20+ years, not a single person from the oldest pump man alive to the top engineers for major pump and control companies have been able to prove me wrong.  I am sure that makes me sound arrogant, but I am not.  It is winning these arguments for so many years that made me so confident, and I humbly apologize if that makes me sound arrogant.  I do not believe I am better, smarter, or more important than other people, which is the definition of arrogance.  After many years I am simply confident, as I finally learned how to do the math and interpret the facts correctly.

I can’t count on all my fingers and toes the number of people who ended this argument by telling me “I am entitled to my own opinion”, yet can’t show a single bit of proof to back up their “opinion”.

I also cannot count on all my fingers and toes those who called back to apologize when they realized everything I said was correct.  So there are a few good pump installers and engineers who understand this stuff.  I am fortunate to have become friends with many of them. Unfortunately there are only a very few good ones who really understand. 

I know this is a complicated subject as it has taken me 40+ years to get to this point, and I am far from knowing all there is to know.  I still learn something new everyday, which makes this business enjoyable for me.  I am always willing to share what I have learned so far. 

Homeowners and water users are smart to educate themselves as much as possible.  Without educating yourself on the subject you could easily mistake arrogance for confidence.  Only a tiny fraction of all pump installers and engineers understand the basic concepts of how pumps really work.  The more arrogant they are, the more name-calling they do, the more they tell me I am entitled to my own opinion, the less they really understand.  The intelligent ones will quietly ask a few questions, study a few pump curves, and finally see where they have been thinking wrong all these years.

“keep your opinion and I’ll keep mine.”  You opinion doesn’t change the facts.  I am not offering an opinion on this subject.  I am simply stating facts and posting proof to back it up.  Name-calling is a last act of desperation, when you have no proof to back up your accusations.