CSV Question - Best of Both Worlds

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w30bob

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Hi Guys,

I understand the benefits of a CSV and how it works, but I want to optimize it for my needs. I get that for large water demands the CSV stops the pump cycling and provides a continuous pressure while the demand exists. But I also need to address the cycling that occurs when I just need a small amount of water many times a day.

We live in a 3 bathroom house, but it's just me and my girlfriend. So the large water demands come from washing clothes, showering, watering the lawn, washing the car, etc. But for health reasons my girlfriend flushes the toilet many times a day, which is a small (2 gallon?) water demand. So (assuming I understand CSVs) wouldn't the best thing for me to do would be to install a CSV with a pretty LARGE pressure tank?

This way when we demand lots of water, say for a shower, the tank empties and trips the pressure switch and the CSV keeps the pump running until we're done showering.............which reduces the amount of times the pump cycles to just once. And then when we use a little bit of water many times (like flushing a toilet) the large pressure tank would keep the pump from cycling each time we flush the toilet (which it would do each time or two with a CSV and a small pressure tank). Wouldn't that be the BEST of both worlds? Or am I missing something? To that end, wouldn't everybody benefit from a CSV with a LARGE pressure tank to deal with both high and low water demand events? I just don't see the downside to having a large pressure tank and a CSV, other than space for the pressure tank, which you'd have already if you're replacing your existing bad tank.

If this was covered previously in another post I apologize. I did look thru a few pages of posts but ran out of time to read stuff. Thanks for your help on this.

regards,
bob
 

Valveman

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Sure a CSV with a large tank is the best of both worlds, but completely unnecessary. The CSV will eliminate so many cycles for long term water use like showers and watering the lawn, that you can never make up the difference even if you flush a toilet a hundred times per day. And when you flush the toilet multiple times in a row, the CSV just keeps the pump running continuously until the toilet has filled after the last flush, as in only 1 cycle.

On average a CSV with a small tank will cycle the pump exactly as many times per day as a system with a large tank and no CSV. So a system with a CSV and a large tank will cycle many times less than normal, which is good but not necessary.

The main drawbacks of the big tank is the hefty price, and having to wait 10 minutes in a shower with pressure decreasing from 60 to 40 PSI before the pump starts and the CSV starts delivering a strong constant 50 PSI, which will seem like twice as much shower pressure.

A large pressure tank also waste heat. With an 80 gallon tank, which only holds 25 gallons of water, and with average house use, you are bringing in at least 300 gallons of cold water into the house everyday. The cold that comes off that water every time the tank is refilled probably won't add up to much heat loss, but it is still an unnecessary loss.

Then even if you are replacing an old tank and already have the space for it, that space could be better used for something else. I hear stories all the time about what people do with that extra space. It maybe just an extra place to store a couple of bicycles, but it could also open up space for a work shop, enlarging a bathroom, or other such things.

I know the thinking that you need a large tank. But your water comes from the well and pump, not the tank. The tank is and has always been just a means of reducing the number of cycles. And when you have a CSV to do that for you, the tank is almost a moot point. Notice all the "new" so called tankless controls and VFD systems on the market that use a very small tank. Manufacturers are finally realizing big tanks are unnecessary when you have the proper pump controls.

We have been leading the constant pressure craze for 24 years now and others are finally starting to see the light. But with almost a quarter of a century testing and perfecting pump control systems, we were the first to realize constant pressure sytems make big tanks obsolete. Save space and money and just get the small tank. At the most up-size to the 10 gallon tank instead of the 4.5 if make you feel better. But take that 500 bucks for the big tank and go on a nice vacation or buy the girlfriend something nice. You will get a lot more for your money. :)
 

PumpMd

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Look at starts per day in a 24 period on your motor size. Around here, it's either 300 or 100 starts. Your not going to come close to the 300 on the small tank with a CSV. I bet you wouldn't even hit 100 starts per day in a 24hr period. I believe valveman has tested this around 70 starts per day. How big was the house (number of taps used) and the number of people living there valveman?
 
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w30bob

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Hi PumpMD,

Sure, here's a typical 24 hour period........60 toilet flushes + 60 hand washings + 2 showers + 10 short bursts (washing vegetables, preparing food) + 10 miscellaneous short bursts (filling the dog's water bowl, getting water to my chickens and ducks, filling a gallon jug to water the plants, etc.). We only do wash once a week and don't wash cars or water the lawn in the winter.......so adding that all up is around 140 short events and 2 long events per day. That's what I'd like to optimize for.

thanks,
bob
 

Valveman

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If any of those 60 flushes are second flushes, the pump will still be running and there will not be another pump cycles. Any second, third, or however many times you want to stand there and repeatedly flush the toilet the pump will continue to run until you stop doing that. If all 60 flushes are individual flushes, then the pump will cycle 60 times. But I assume the had washing will be immediately following the toilet flush, so again the pump will still be running and there will not be any additional cycles for hand washing. And when you flush and then turn on a shower, there is not even an extra pump cycle for the shower.

Anytime you flush a toilet or use water anywhere, you have between 30 seconds and 90 seconds to turn on water again, without causing an extra pump cycle. It takes that long for the little pressure tank to fill and the pump to shut off. So if you use water again within a minute or so, the pump is still running and does not add to the cycles.

And of course a shower or watering the lawn would only cause 1 cycle with a CSV, no matter how long you are in the shower or how long you water the yard. So I am guessing you would get about 60-70 cycles per day using the CSV and small tank. A lot of people use little spurts of water, or just barely open a hose when watering, because they think that is easier on the pump. When they finally figure out that pumps like to run, they become aware of pump cycling, and start filling the bowls for the dog, chickens, ducks, and plants all at the same time, because it is better for the pump.

I am adding up maybe 400-500 gallons per day use the way you describe it, without watering the lawn, which could add hundreds more gallons per day. So even a 40 gallon tank (10-12 gallon draw) without a CSV would cause the pump to cycle 40-50 times per day for just house use. That can easily increase to 100-300 cycles per day when watering the yard.

So the 60-70 cycles per day using a CSV and a small tank would be fine, because the CSV will completely eliminate any cycling while you are watering the yard or other long term uses of water. When you have a sprinkler running in the yard all day, the pump is already running because of the CSV. So on those days your pump only cycles once, no matter how many times you use water in the house at the same time.

But by all means if you want a larger tank, get one. With the CSV you will just soon realize you didn't need a large tank.

I am constantly amazed at how no one even questions the little tanks on those variable speed pump systems. VFD type systems cannot even use the entire amount in the small tanks. So the way you describe using water WOULD cause 100- 200 cycles per day with one of those. Installers will tell you that is just fine.

But when using a CSV, which can utilize the entire amount of draw from any size tank, they get it in their head that they need a larger tank. No question a CSV with a larger tank is the best of both worlds. But the CSV with a small tank does such a good job, you will never be in the other world to need it.
 

w30bob

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Hi Valveman,

I get it. I'll call Karen tomorrow and order my CSV. I read a reply of yours on another post regarding installing a CSV on an old pump and you talked about checking the amp draw while the pump was back pressured to see if the thrust bearing was still intact............I'll do that too when I install the CSV. If my pump is on its deathbed I may as well get ready to replace that too.

And let me say thank you for not just your replies, but the way you reply. I can tell you must read posts like mine and bang your head on the wall asking yourself "why don't these folks get this..........a CSV just makes so much sense!". I've read a bunch of your replies on other posts and I can sense your frustration........but you always reply kindly, take the time to provide a full explanation and never talk down to us newbies snd amateurs not in the plumbing business. I appreciate that.

thanks,
bob
 

PumpMd

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It would roughly cycle in between 4-5mins on a 10gpm pump (depends on how long it takes to build pressure against what you are running) at 1/2 the flow rate (5-6gpm) of your drawdown on a 40gal tank.

How long does it take someone to water a lawn? 2-8hrs
 
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w30bob

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Hi PumpMD,

It usually takes a couple hours............unless you get easily distracted, forget about it and let it run all night.

:O)

regards,
bob
 

Valveman

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Hi Valveman,
I get it. I'll call Karen tomorrow and order my CSV. I read a reply of yours on another post regarding installing a CSV on an old pump and you talked about checking the amp draw while the pump was back pressured to see if the thrust bearing was still intact............I'll do that too when I install the CSV. If my pump is on its deathbed I may as well get ready to replace that too.

And let me say thank you for not just your replies, but the way you reply. I can tell you must read posts like mine and bang your head on the wall asking yourself "why don't these folks get this..........a CSV just makes so much sense!". I've read a bunch of your replies on other posts and I can sense your frustration........but you always reply kindly, take the time to provide a full explanation and never talk down to us newbies snd amateurs not in the plumbing business. I appreciate that.
thanks,
bob

Thanks Bob. From someone who has tried every kind of pump control available, the CSV does make a lot of sense. I get frustrated that maybe I am just not explaining it well enough. I keep thinking I’ll find the right way to explain it and help everyone understand.

I shouldn’t harp about the small tank so much, because the CSV really does work fine with any size tank, and a big tank along with a CSV is the best of both worlds. But I want to emphasize that no matter the size of the tank, the CSV is controlling the pump and the water is going right past the pressure tank, straight to the shower, faucet, etc., for as long as you are using water.

Only during times when there is no other water already being used in or around the house and you need a small spurt for something, is the tank even being used. Usually in a household all the occupants will use water at about the same time. So while one is making a pot of coffee, another is in the shower. So the pump was already running and the pump didn’t have to cycle for the pot of coffee. If the washing machine is filling when you flush a toilet, two more cycles combine into one. The pump may just run steady for 20-30 minutes while everyone is getting ready for work and school. The same thing may happen again before bedtime, and the 60 cycles per day you were worried about turned into 25 cycles because of the timing of everyone’s use of water.

But the CSV is a show me type of thing. I had to study it working for a long time myself to figure out how all this works. And I don’t mind explaining it because I usually get a lot of thanks after they finally see it work. A lot of my phone calls are just as nice as the reviews on our products, and it makes it all worthwhile for me.

But every once in a while I get someone who doesn’t even understand that cycling is the number one killer of pumps. I still try to be nice when I remind them that there are 1440 minutes in a day, and 4-5 minutes cycles could easily be 300 cycles in a 24 hour day. That is even 100 cycles in an 8 hour irrigation zone, which is fairly common. And how long it takes to water yard depends on how big the yard is and how dry the conditions. I know of lots of systems that do water something 24 hours a day. These are the kinds of systems where I learn about how bad cycling 100 or 300 times a day is for a pump, and how much better it is to have a CSV and let the pump run 24/7. These have given me lots of accelerated tests on pump systems over many years. And if the CSV can make pumps like that last many times longer than normal, you also won’t be able to flush enough toilets to cause a problem or require a larger tank.

It will most certainly hurt your pump to cycle all night. Countless times I have heard from people that say, “they left a hose running and forgot about it”, which let the pump cycle “normally” for a day or two. They ran out of water and had to call the pump man. After purchasing and installing the new pump, they couldn’t get it to stay off after it filled the tank. Then they find the garden hose running behind the house and the reason for having a new pump is obvious (cycling). Now that may not have been the first time they forget and left the hose running, but I bet it will be the last. (unless someone tells them about a Cycle Stop Valve) :)
 
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PumpMd

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I guess you forgot about Xfaxman that left his faucet running all night multiple times going to his cattle or horses on a CSV and found something special in the screen off the kitchen sink (pump impellers). The in well tank was waterlogged but let's see what kind of pump life he gets next time around with your psidekick kit and maintenance.

from Valveman: When the tank does loose its air, the CSV keeps working so the pump doesn't rapid cycle a hundred times for a shower. The pump just shuts off instantly when the faucet or shower is turned off. With a CSV the pump can survive a "long time" with a "waterlogged" tank as long as there are "no small leaks" and the pump stays off until someone uses water.
 
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Valveman

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I guess you forgot about Xfaxman that left his faucet running all night multiple times going to his cattle or horses on a CSV and found something special in the screen off the kitchen sink (pump impellers). The in well tank was waterlogged but let's see what kind of pump life he gets next time around with your psidekick.

The extra cycling from a water logged tank will certainly cause impellers to come apart quickly. Lets just see how long his system will last now that he has a Pside-Kick system. I said that same thing about some of the first CSV systems back in 1993, and I am still waiting............ :)
 

Valveman

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The motor was fine....;)

Cycling from a water logged tank is hard on the pump and the motor. One impeller design causes the pump to go first, another design causes the motor to take the brunt. But make no mistake, cycling is the number one reason for the destruction of most pumps and/or motors.
 

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w30bob:
Its all in the timing - I have been thinking the exact same thing for a couple weeks and I just logged on to ask my version of the same question.
I ordered the pside-kick a few weeks ago and have not installed it yet (for other reasons.)
When I spoke with valveman, I was pretty comfortable but still upgraded to the 10 gallon tank. Then I had the thoughts as you expressed. I don't water the lawn and with 3 young grand kids around all of the time, I was becoming concerned about all of the short bursts of water needed for the constant drink, wash, flush, etc.
The discussion above puts me to ease - mostly..... I may still go with a larger tank. I have a 30 gallon tank that is currently in my system that I could use.

Ditto to your comments to and about valveman. I spoke with him live as well and he was just as helpful, informative and knowledgeable.
 

Craigpump

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Cycling from a water logged tank is hard on the pump and the motor. One impeller design causes the pump to go first, another design causes the motor to take the brunt. But make no mistake, cycling is the number one reason for the destruction of most pumps and/or motors.


You're wasting your time trying to talk sense to someone who's mind is closed, everything he learned in life he learned from pappy or whoever.....

His last IM to me went like this.
 

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Valveman

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Yeah I was pretty sure you other pump guys were getting IM's about me. He wants so badly to believe that cycling doesn't hurt a pump, because his uncle said so. Even though he himself posted many articles from engineers that prove cycling is the number one killer of pumps.

I am surprised that you were "silent" and that none of the others joined him in trying to convince me how wrong I am. lol

If we would all just listen to him we could learn a lot of things, like "flow inducer shrouds don't really help cool a motor", and "cycling on and off has never destroyed a pump in all of human history". :)

I won't post my IM's from him, but WOW. It is hard for me to take when everyone else I help or talk to say things like the following.

Hi Valveman,
And let me say thank you for not just your replies, but the way you reply. I can tell you must read posts like mine and bang your head on the wall asking yourself "why don't these folks get this..........a CSV just makes so much sense!". I've read a bunch of your replies on other posts and I can sense your frustration........but you always reply kindly, take the time to provide a full explanation and never talk down to us newbies snd amateurs not in the plumbing business. I appreciate that.
thanks,
bob

w30bob:
Ditto to your comments to and about valveman. I spoke with him live as well and he was just as helpful, informative and knowledgeable.
 
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