Chronic community pump failure

[andre3000]

Hello evryone,
I live in a community that lives off a well that produces 55 gpm+, about 70 house.
For years now water shuts off, pumps get fixed and water turn brown now and then.
The system is made of a 350' well, 2 large reservoirs with min max sensors which shut off booster pumps if out of range, 2 booster pumps, one emergency pump, an air pump to a pressure tank with two pressure sensors driving the 2 booster pumps.

The last time it failed, one BP had to be rebuild, the auxiliary inbuilt sensors and electric kept shutting on and off, and pump 2 does trip occasionaly so we switched to the well pump for pressure. Each time work is done the water turns very brown.

I wanted to hear stories of cascading failure and their root cause, see if this can inspire some lasting solutions on our side.
thank you.

 

[Valveman]

You said "pressure sensors", which means they are controlled by a Variable Frequency Drive? If so, that is your problem. VFD's are made to make a lot of profit from, and if they lasted any time the installer would not be making as much money. Get rid of the VFD's and install Cycle Stop Valves instead and you will never have to worry about your water again.

I guess you could also be talking about a regular pressure switch? Which means the pump are cycling on/off to death on a regular basis. Either way a CSV is the way to have a dependable, inexpensive, and long lasting pump system.

See this link from a similar system one of my best installers sent me today.
http://www.cyclestopvalves.com/smf/index.php?topic=2334.0

 

[Sponsor]

 

[andre3000]

I don't know so here is how i saw it work: pressure tank psi drops below the min threshold -> current goes through a switch that alternates between pumps ->
first small relay closes -> which closes another large relay -> which kick starts the booster pump. The kick start is brutal.

You said "pressure sensors", which means they are controlled by a Variable Frequency Drive? If so, that is your problem. VFD's are made to make a lot of profit from, and if they lasted any time the installer would not be making as much money. Get rid of the VFD's and install Cycle Stop Valves instead and you will never have to worry about your water again.

I guess you could also be talking about a regular pressure switch? Which means the pump are cycling on/off to death on a regular basis. Either way a CSV is the way to have a dependable, inexpensive, and long lasting pump system.

See this link from a similar system one of my best installers sent me today.
http://www.cyclestopvalves.com/smf/index.php?topic=2334.0

View attachment 41345

 

[Craigpump]

You said "pressure sensors", which means they are controlled by a Variable Frequency Drive? If so, that is your problem. VFD's are made to make a lot of profit from, and if they lasted any time the installer would not be making as much money. Get rid of the VFD's and install Cycle Stop Valves instead and you will never have to worry about your water again.

I guess you could also be talking about a regular pressure switch? Which means the pump are cycling on/off to death on a regular basis. Either way a CSV is the way to have a dependable, inexpensive, and long lasting pump system.

See this link from a similar system one of my best installers sent me today.
http://www.cyclestopvalves.com/smf/index.php?topic=2334.0

View attachment 41345

We pulled a BF20 drive the other day....pos. And replaced it with an Intellidrive, not that I wanted to, but the motor was good, the cable good and there was no reason to change what was in the well.... Once you buy into the VFD way of thinking, your stuck...

 

[Valveman]

I don't know so here is how i saw it work: pressure tank psi drops below the min threshold -> current goes through a switch that alternates between pumps ->
first small relay closes -> which closes another large relay -> which kick starts the booster pump. The kick start is brutal.

Then there is no VFD. The pumps are just being cycled on/off to death. That regular starter makes it easy to add a CSV. Just put a CSV on the discharge of each pump. The cycling will go away, and so will a lot of other problems. A CSV will make the pumps last decades, not months as you are use to. Most of the systems like this we put CSV's on in 1993 are still working, and have not given any problems. The people who originally put in these systems are no longer even around. The water users don't even know they have a pump system, water just comes out of the faucets when they open one, so they have never thought about it.

 

[andre3000]

Thanks for the recommendation. You designed CSV ?
Can you explain how CSV, VFD and regular pressure switch work and tell me more about their impact on performance and lifetime?
Also what is a pump' discharge?

Then there is no VFD. The pumps are just being cycled on/off to death. That regular starter makes it easy to add a CSV. Just put a CSV on the discharge of each pump. The cycling will go away, and so will a lot of other problems. A CSV will make the pumps last decades, not months as you are use to. Most of the systems like this we put CSV's on in 1993 are still working, and have not given any problems. The people who originally put in these systems are no longer even around. The water users don't even know they have a pump system, water just comes out of the faucets when they open one, so they have never thought about it.

 

[Valveman]

Lets just start with the difference between a regular old pressure tank only system and a CSV system. This video is the best way I know how to explain it.

 

[andre3000]

thanks. CSV varies pump flow instead of the traditional binary hammering. This makes much more sense.
Now what is the difference between a CSV and a VFD?
Do normal pumps handle varrying amp? And which piece of equiment carries the amps in a CSV system?

 

[Valveman]

Most people do not realize the power consumption will reduce by simply restricting the flow from a pump almost exactly the same as it does when you slow the pump down with a VFD. Here are a couple more videos to explain that one.

 

[andre3000]

CSV varries flow and keeps RPM, VFD varries RPM.

1. how does CSV varry flow?
2. doesnt lowering flow increase pressure and put more stress on pump
3. what else is required when installing CSV?
4. can traditional on/off coexist with CSV (if we want to test CSV with non CSV fallback)

 

[Valveman]

CSV varries flow and keeps RPM, VFD varries RPM.

1. how does CSV varry flow?
2. doesnt lowering flow increase pressure and put more stress on pump
3. what else is required when installing CSV?
4. can traditional on/off coexist with CSV (if we want to test CSV with non CSV fallback)

The CSV varies flow just like any valve, it reduces how much flow is let out of the pump. And yes this increases pump pressure, which actually decreases "stress" or the load on the pump/motor. All you need is a CSV, small pressure tank, and a pressure switch, like the above pic shows. You have been testing the "traditional" on/off pressure tank only system for years. You described all the problems you are having with that system. The CSV just solves the problems you are having by not letting the pumps be cycled on/off to death.

The main difference is with a CSV you only need a small, maybe 80 gallon size pressure tank. Without the CSV you need a pressure tank many times larger than the one you have now. But a larger tank only reduces the cycles, where a CSV will eliminate the cycling. Maybe you need to watch those two videos again as they show how the motor load is decreased (less stress) when the CSV decrease the pump flow to match the demand.

 

[andre3000]

The CSV varies flow just like any valv

So it is a servo motor driving a valve, doesnt that move or add a failure point?

 

[Reach4]

So it is a servo motor driving a valve, doesnt that move or add a failure point?

It does not have a power supply or motor.

 

[andre3000]

It does not have a power supply or motor.

How does it varry the flow to match demand?!
Sounds like the sort of magic I want to learn

 

[Reach4]

How does it varry the flow to match demand?!
Sounds like the sort of magic I want to learn

It is like a pressure regulator, but it always allows a minimum amount of water through. If the usage is more than the minimum flow, the pressure holds constant. If usage is less or none, the pressure rises at a controlled rate until it hits the cut-off pressure at the pressure switch.

If you used a 50 PSI CSV with a 40/60 PSI pressure switch, the pressure would spend most of its time at 50 when water is being used for more than a bit.

A centrifugal pump, unlike a positive displacement pump, inherently pumps water at a lower rate in the face of backpressure, and non-intuitively draws less current under those conditions.

 

[Valveman]

A CSV just works from pressure. If the spring is adjusted to say 50 PSI, the spring pushes the valve open when there is less than 50 PSI in the system. The diaphragm on the other end of the spring pushes the valve closed when the water pressure is higher than the spring tension. So the CSV increases or decreases the flow rate to try and maintain 50 PSI. When the pressure drops to 49 PSI it knows you need more water and opens up to supply more water. When the pressure is at 51 PSI it knows you have turned off some water and reduces the flow from the pump to bring the pressure back down to 50 PSI. It is so simple is does seem like magic, but its not.

 

[andre3000]

Thanks @valveman and @Reach4, I understand now.

It is very ingenious and elegantly low tech.

Why then is it not standard?

 

[Valveman]

The CSV is a disruptive product. Just think how much money the contractor, pump manufacturer, tank manufacturer, and others would not be making if that pump system ran for 30 years without any repairs. Kind of like getting a fuel additive that would make any car get 100 MPG. Do you think the guy who owns the gas station or the oil company would tell you about it. I think not. They would try to keep you from finding out about it, and if you did, they would tell you it will destroy your car engine, cause toxic emissions, or anything else they could think of to keep you from using it. Same with the CSV.

But a disruptive product is a good thing for the end user. You just have to find out about it on your own, and usually go against the advice of the persons who have been profiting at your expense for so long.

 

[Craigpump]

My advice to anyone considering a VFD, go price out a drive unit plus the installation. The drive we installed last Saturday lists at over $1800.00 plus the service call & installation.

Yeah, tell that to a working man with a wife, two kids, car payments, mortgage............

 

[Valveman]

My advice to anyone considering a VFD, go price out a drive unit plus the installation. The drive we installed last Saturday lists at over $1800.00 plus the service call & installation.

Yeah, tell that to a working man with a wife, two kids, car payments, mortgage............

I am glad there are still some honest pump guys like you out there. I talked to one the other day that said he won't install anything but VFD systems anymore. Said he didn't care if the customer got mad and never called him again. He makes more selling one of those $1800 VFDs than he does in 30 years after installing a conventional or CSV system. Gets his money up front and then he is done with you. Said sometimes the VFD even last past the warranty period and he gets to sell another one. "Cha-ching, just extra money when that happens." And I quote.