Slow Down Pentek Intellidrive

[Ironbar]

I have a Pentek Intellidrive that has a 20 GPM pump attached. My question is: Can I slow down the pump so it only pumps 10 or 11 GPM?

I see in the manual under Motor setting that you can change the Max Motor Frequency. Under description it says: Maximum frequency (speed) motor will run.

Any help would be appreciated.

Thank you.

 

[Valveman]

If it is working properly it will automatically adjust itself to 10-11 GPM, as long as you are only letting 10-11 GPM out the faucet.

 

[Sponsor]

 

[Boycedrilling]

Think of the intellidrive as an electronic cruise control. It senses pressure rather than mph in a car. It is set to maintain a specific pressure. I normally program then for 50 psi. I then program them to drop 15 psi before the pump starts. When the pressure drops to 35 psi the pump turns on it will then run at what ever rpm it takes to reach and then maintain 50 psi. If it can maintain 50 psi for a specified time, at minimum speed, it knows that no water is being used. I then program it to boost the pressure an additional 3-5 psi, then shut off until the pressure drops again. I also use a full sized pressure tank. I am using the full 20 psi drawdown of the tank this way.

So yes the pump will only pump as much as the fixture allows.

Also yes, you can limit the maximum speed of the pump to less than full speed and this will reduce its maximum flow. You could reduce max hertz to say 54 hz and see what it does. Fool around with the settings at your own risk however. Or buy the intellilink for it from me and I can reprogram it from my iPad. It will also text me any faults that occur.

 

[Boycedrilling]

On the commercial grade vfds, I can integrate a flow meter and program the pump to run at a preset flow rather than pressure. I can also program it to pump a specific quantity of water over a specific time period, then shut down until the time period had ended. For example if I wanted to limit the quantity pumped to 5,000 gallons per 24 hrs, I could program those parameters into the drive.

 

[Valveman]

This discussion always reminds me of the ink pen NASA made for Astronauts to take notes with. The pen needed to work in zero gravity, boiling hot or sub zero temperatures, upside down, sideways, and write on any surfaces. Nasa spent millions designing the pen, and each one sent into space cost an additonal million or two to manufacture. The Russians space program had the same problem. However, they discovered all of this could be accomplished with a regular #2 pencil. There are two products that would accomplish the same job. One cost millons of dollars and had a potential to fail. The other cost a nickle and never misses a beat.

 

[Valveman]

Think of the intellidrive as an electronic cruise control. It senses pressure rather than mph in a car. It is set to maintain a specific pressure. I normally program then for 50 psi. I then program them to drop 15 psi before the pump starts. When the pressure drops to 35 psi the pump turns on it will then run at what ever rpm it takes to reach and then maintain 50 psi. If it can maintain 50 psi for a specified time, at minimum speed, it knows that no water is being used. I then program it to boost the pressure an additional 3-5 psi, then shut off until the pressure drops again. I also use a full sized pressure tank. I am using the full 20 psi drawdown of the tank this way.

So yes the pump will only pump as much as the fixture allows.

Also yes, you can limit the maximum speed of the pump to less than full speed and this will reduce its maximum flow. You could reduce max hertz to say 54 hz and see what it does. Fool around with the settings at your own risk however. Or buy the intellilink for it from me and I can reprogram it from my iPad. It will also text me any faults that occur.

Think of the CSV as a "mechanical" cruise control. It senses the pressure instead of mph in a car. It has a simple adjustment bolt that can be set to maintain a set pressure. It is normally set to maintain 50 PSI. A standard and reliable pressure switch can be set to turn the pump on when pressure drops 15 PSI or so. When the pressure drops to 35 PSI, the pressure switch starts the pump, and it will fill the tank to 50 PSI, at which point the CSV starts regulating the pump flow to match the usage. The CSV has a 1 GPM minimum built in, because these size pumps need a minnimum of 1 GPM to prevent destruction from overheating. When no water is being used, the 1 GPM minimum in the CSV has no place left to go except the pressure tank. So the pressure is "boosted" 3-10 PSI and the pressure swith will shut off the pump at 55 PSI or so. You can use the CSV with a full size tank. This way you get the full drawdown from any size tank before the pump restarts.

So yes the CSV will only let the pump produce whatever the fixture allows. There is no programming required and no faults will occur.

The biggest problem is that most people do not understand that the amps will drop the same way when a full speed pump is restricted with a CSV, as it does when the motor is slowed with a VFD.

The benefits of the CSV is that there is no programming required, no cooing fans or filter to clog or fail, no chance the CSV will be destroyed by lightning, or the many other things that cause electronics to fail.

Also a motor controlled by a VFD cannot run at as low flow rates as a motor/pump controlled by a CSV. This is because the harmonic content of the power created by a VFD causes additional heat in the motor. So even though the amps are reduced, the motor still needs as much flow to stay cool as a full speed, full flow pump and motor. For this reason the minimum speed of the VFD needs to be set to maintain the minimum flow needed to cool the motor. Letting the motor run for long periods of time at really low flow, or running at zero flow for short periods of time are hard on the motor.

Plus any time you vary the speed of the pump/motor, you are running it at the resonance frequency of every component in the pump or motor, which causes vibration and reduces the life expectancy.
With a CSV the pump/motor always runs at full speed, so there is never a problem witih resonance frequency vibration. And even though the pump is always at full RPM, the amps vary with the flow rate, the same as the do when varying the RPM with a VFD.

I never fault an installer for installing what the customer ask for. But the customer should do some research and figure out that the VFD will cost them thousands of dollars over the years, and will not do as good a job as a CSV, which can be had for as little as 63 bucks.

 

[Boycedrilling]

I did pickup 3 cycle stop valves yesterday at my supplier. I have a customer that it will be the exact fix to his problem. Judy not sure if the 1" valve is big enough for his flow. So I also got the metal and pvc 1 1/4" valves.

 

[Valveman]

I appreciate that! And I am not totally against VFD's. There are some good applications for VFD's. Just not very many in the water well industry with centrifugal pumps. I have an Inverter (VFD) on a new heat pump I put in. The compressor in the heat pump is positive displacment, and slowing down the RPM saves a lot of energy, unlike when using a VFD on a centifugal pump. I talked to a pump man the other day who uses VFD for environmental wells. He drops a transducer down the well and sets the VFD to maintain a specific well level. That way he can skim the contaminants off the top of the water. He said lightning and just electrical problems have taken out several of the VFD's, so they are only averging maybe 5 years. But for what he is doing with those environmental wells, the short life is not that much of a problem.

VFD's have also been good for the CSV business. We designed the CSV to replace VFD's, and have been doing so since 1993. Contrary to what many people think, the idea of a VFD is older idea than the CSV. So the more VFD's installed, the more there are to replace with CSV's. VFD's are so heavily marketed, that it makes selling CSV's that much easier. Customers get use to the constant pressure from the VFD, and it breaks the ground on the idea of only needing a small pressure tank. Once they realize the amps drop the same with a CSV as they do with a VFD, the next time the VFD starts giving problems, they are easy to switch over to a CSV.

 

[SpokanePumpGuy]

You guys and your CSVs!

Not to rattle any cages here, but a CSV is a pump killer. Eats impellers. Yeah, it regulates the flow, and drops the amps as the flow is reduced. Yet no one mentions that a single phase motor should run a consistent amperage, with the exception of static drop.

A three phase motor DOES NOT generate heat like a single phase, and it is specifically designed to operate at varying hz. Additionally, as your valve is 'regulating' flow, it is also creating a dead head on the pump, even more so at lesser flow rates and higher pressure. ALL pumps are designed to flow water as freely as possible. That's why we put pressure tanks in place prior to any fixtures. And no, installing the valve after the tank will not work, as the switch now regulates said pressure.

A VFD constant pressure is exactly that, unless used at open flow rates.

Keep installing those CSVs. I'll keep tearing them out when I replace the pumps they kill.

 

[Bannerman]

I'm getting the popcorn ready.

 

[Valveman]

You guys and your CSVs!

Not to rattle any cages here, but a CSV is a pump killer. Eats impellers. Yeah, it regulates the flow, and drops the amps as the flow is reduced. Yet no one mentions that a single phase motor should run a consistent amperage, with the exception of static drop.

A three phase motor DOES NOT generate heat like a single phase, and it is specifically designed to operate at varying hz. Additionally, as your valve is 'regulating' flow, it is also creating a dead head on the pump, even more so at lesser flow rates and higher pressure. ALL pumps are designed to flow water as freely as possible. That's why we put pressure tanks in place prior to any fixtures. And no, installing the valve after the tank will not work, as the switch now regulates said pressure.

A VFD constant pressure is exactly that, unless used at open flow rates.

Keep installing those CSVs. I'll keep tearing them out when I replace the pumps they kill.

Lol! Almost 30 years and a million pumps working with a CSV and not a single pump or motor failure of any kind. You are absolutely wrong! I wish pump guys would quit saying stupid stuff like that and making everyone in the pump industry look ignorant. I have offered for 30 years to personally replace at no charge any pump that was destroyed by a CSV. If you have any pumps that were destroyed by a CSV I will replace them at not charge. However, whatever failures you are seeing are not caused by a properly functioning Cycle Stop Valve as I have yet to see any damage caused by a CSV. To the contrary, every pump with a CSV will last several times longer than just a pressure tank system, and much, much longer than any expensive VFD system. Yet here is another idiot pump man claiming CSV's are bad for pumps. I would say, this pump man is bad for pumps, not the CSV.

The CSV actually works so well that many major pump companies blacklisted it in 1994. The pump engineers said, "The CSV makes pumps last longer and use smaller pressure tanks". Then the CEO of the company said, "This company makes pumps and tanks, so anyone who mentions a CSV will be fired immediately". Over the years I heard the same story from engineers who retired from Goulds, Berkeley/Pentair, and Grundfos and many others.

We all know why pump guys like selling VFDs. They make more money selling expensive and short lived VFD's these days than they do selling pumps. Send me any pump you think was destroyed by a CSV and I will do an autopsy on the pump and tell you the real reason for failure, which I can assure you will not have anything to do with a CSV. Get any of the above mentioned pump companies to put in writing that a CSV is bad for pumps, and I will send you a thousand dollars. You won't be able to get this in writing because they know I would own that company after we went to court.

There are laws that keep people from telling false information, especially if it hurts someone's business. If anything I said about VFD's was incorrect those pump companies would have their lawyers on me in a heartbeat. You should be careful to at least know the facts before popping off like that. I don't want to go after the small businesses. You pump suppliers and manufacturers know that and pump you up at the open houses and stuff to get you to make these liable statements so they don't have to pay for it.

Anyone in the Spokane area needs to be aware that the Spokanepumpguy is an idiot who will cost them dearly.