LOL! I feel ya! I have been getting push back since I filed for five patents on the idea in 1993. That's right! TWENTY SEVER YEARS AGO, AND FIVE PATENTS! And in 27 years there has never been a single pump damaged by a CSV. On the contrary, CSV's have made hundreds of thousands of pumps last longer than they did previously. Many of those first test cases I installed almost 30 years ago are still running today, when they were lasting an average of 7 years prior to installing a CSV. Most of the first cases that tried CSV's had nothing to lose, as they had already tried larger tanks, VFD's, and many other things and still couldn't make the pumps last. The CSV's made test cases that preciously lasted only a year or two last more than 12 years. Other systems where the pumps would only last maybe 3 to 5 years, adding a CSV made them last 20+ years so far. The CSV more than doubles the life of the pump, and many have lasted 600% longer so far. And if you don't think the US Patent Attorneys went over back pressure and motor cooling with a fine-tooth comb, think again. But it did take 6 years for even the smartest engineers in the US Patent office to research and figure out it would work just as I said and issue the patents.
I fully understand why pump guys think that way. I thought exactly the same way for the first 20 years of the 50 I have been working with pumps. The words "chocking" and "throttling", which is what the CSV does, are negative words to start with. "Deadhead" and "back pressure" are considered negative words to any pump man. But the way a CSV works is one of the only true counter intuitive things I can name. "Chocking, throttling, or increasing back pressure" on a piston or gear type pump would be a bad thing. But the centrifugal impeller, which is what all pumps in this industry are made with, has a couple of characteristics that are just the opposite of a piston/gear pump and just the opposite of what our brains tell us is correct.
Increasing back pressure on a pump with a centrifugal impeller is good for the pump. Back pressure makes the pump draw lower amps or power and run cooler. Running a centrifugal impeller with too low a back pressure is the hardest thing for a pump. Low pressure means high flow, high amps, high motor heat, and possible cavitation. Any pump man knows when a pump is drawing too many amps and tripping the breaker, restricting the flow a little with a gate valve, ball valve, or Dole valve will reduce the amp draw, make the motor run cooler, and stop tripping the overload. I don't know why it is so hard for us to understand that continuing to restrict the flow further would make the motor draw even fewer amps and run even cooler. The only way back pressure will hurt the pump is if you close a valve all the way and "deadhead" the pump. Even then it is not the closed valve or the high back pressure it creates that hurts the pump, it is the fact that zero water is moving. With complete deadhead and zero water moving the water in the pumps gets hot quickly and the pump will not last long.
However, deadhead has absolutely nothing to do with a CSV. The CSV can never completely close. The CSV can never deadhead a pump. The minimum flow through the CSV has been carefully researched to be about 3 to 5 times more than it really takes to keep a pump cool. You will never get a pump or motor hot with a CSV. It is just the opposite of what some people think, the motor is drawing lower amps and running cooler because of the back pressure from the CSV.
All those pump guys will be much better pump guys when they figure this out. But I understand the counter intuitive part is hard to comprehend. It took me a couple of weeks explaining and showing for some of the engineers at some of the big pump manufacturers to understand how it worked back in 93-94. Their mouths dropped open and the light went on over their heads when they finally understood. But did they take this new product and use it to make all their pumps last 30-40 years instead of the average 7 years? Heck no! They Blacklisted it. The CEO of the pump company said "this company makes a living selling pumps and tanks. CSV's will make pumps last much longer and use smaller tanks. Anyone working for this company and mentions a CSV will be fired immediately." Took me another four years to find this out.
Since then the pump companies have been on a rumor campaign to make people fearful of CSV's. Back pressure, deadhead, cavitaiton, and many other things are said out loud to start the rumors. But there is nothing in their warranty or nothing written to back this up. They know any engineer worth his salt or I can easily prove them wrong and that a CSV can never damage a pump. They know they cannot write anything negative about the CSV or dis-allow warranty for using a CSV, or there would be liable issues because it is not true.
You can get by with a bunch of expensive and troublesome big tanks, but the CSV is a superior way to control a pump and any good pump man knows it. The best way to determine if a pump man knows what he is talking about is the back-pressure thing. If he thinks back pressure makes a pump work harder, he really doesn't have a clue how pumps work. Unfortunately, and maybe because of the rumors the pump manufacturers started, I would say maybe only 5% of all pump men understand this. Also, unfortunately, people keep having to buy new pumps every seven years on average, mostly because they believe the pump men who fell for the CSV rumors.
It is a double-edged sword for me. The rumors make it hard to get people to believe the truth about how a CSV works. But if it weren't for the rumors every pump owner would be demanding a CSV. Every pump company would be selling a version of the CSV, all pumps would last 30+ years, and I would be out of business myself. Planned obsolescence cost consumers millions of dollars they should not have to spend. Planned obsolescence is good for pump companies as well as my business. If every pump had a CSV, nine out of ten pump companies as well as me would be out of business. I am just amazed at how many people keep falling for the rumors.