CSV Minimal Pressure Range and other ?s

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JRC3

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I didn't want to derail the other thread and I have some questions I can't find. Please bear with my long-winded rambling...

Constant pressure systems like the Cycle Stop Valve still use a regular 40/60 or in you case 55/75 PSI pressure switch setting. By having 20 PSI between on and off, a 4.5 gallon size tank can supply a gallon of water, a 20 gallon tank can deliver 5 gallons, and a 119 gallon tank could spit out 30 gallons before the pump starts.
This leads to a question I've been bouncing in my head and wanting to ask for a while. What is the smallest psi window/range a CSV will work? For example. 40/55, 45/55, 40/52? I'm sure it's something you probably have to play with a bit, but what can be expected?

My current submersible had a 30/50 switch. Everything was replaced with a 2 post switch and a 46G pressure tank. 30 psi cut in was a bit low for my shower so I've settled on 38/55 psi. This gives my pump at least 65 seconds of run time and around 9 gallons drawdown from the tank. I want to do a CSV and am hoping I can take the cut out psi back down around 50 and have the cut in around 40. Is this possible?

I wish I could set my cut out around 55 or 60 but the condition of my well is unknown. See, the house was a foreclosure. I replaced the waterlogged 20G P tank in the crawl. Right next to it sat an old 10G, so who knows how many short cycles the pump has had on it. I know 4 people lived here and the septic guy told me there were 7 at one point. These people did very little maintenance and things seemed to only be addressed when they completely failed. The pump seems fine producing around 10 gpm. It is a submersible with no control box. Looking at well reports for my neighborhood, spotty and my house isn't included, I'm guessing it is between 70-100', and installed around 1961 when the home was built, but once again, I'm guessing. To test the septic drain field I let the pump run directly into it for an hour to an hour and half for several back to back days. In other words, the recovery of the well is good. The old P tank had "installed 2001 or 2003" written on it. I think that might be as new as the pump might be if they were replaced together, but who knows.

So back to my question, what range might I be able to set things with a CSV? I would love to hear something like 40/50 or so, if my switch (SqD 2 post), or any other switch even allows this. And then, what could be expected from a 46G pressure tank? I'm guessing around 5 gallon of draw-down depending on the psi and range.

Also, will a pump give signs of failure befor it dies completly? Like will it show signs for a month, or do they just crap out all at once? I've never had a well so I have no experience with them. Luckily I only use about 60 gallons a day. My iron filter frequently use a bunch of water but the pump only cycles once per regen.


Thanks
 

Reach4

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I would love to hear something like 40/50 or so, if my switch (SqD 2 post), or any other switch even allows this.

I think you would need an electronic pressure switch to do 10 PSI differential. The mechanical Square Ds are supposed to only be for a minimum of 20 PSI differential, and compressing the smaller spring increases the differential. Yet you have achieved a 17 differential.

You could put two pressure switches in series -- a mechanical and a new electronic switch. This would be a failsafe measure.
 

Valveman

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Some people say they can't tell the difference in shower pressure as the pump is cycling between 30 and 50 PSI. They must just have weak pressure shower heads to start with, because most people can feel a big difference between 30 and 50 in the shower. And since a 40 gallon size pressure tank holds about 12 gallons of water when working at that pressure, you will see swings from low to high pressure 3-4 times in a shower that uses 36-48 gallons of water.

Just adding a CSV to what you have would help considerably. The pressure would only drop from 50 to 30 once when you start the shower. Then the pump would start and the CSV would hold the pressure at a strong and steady 45 PSI for as long as you are in the shower. But with a 30/50 setting and a 40 gallon tank that holds 12 gallons of water, you will be 4 minutes into a 3 GPM shower before the pump starts and you begin to see the strong constant pressure coming from the CSV.

So at 30/50 a 40 gallon tank has 12 gallons of draw down. At 40/50 it would only hold 6 gallons of water. And with a pressure switch setting of 45/50 the 40 gallon tank would deliver about 3 gallons before the pump starts. When using a CSV 1 gallon of draw down is really all that is needed. However, as Reach said it will be hard to find a pressure switch that will adjust to such a small bandwidth. The regular Square D FSG2 will only go down to about 17 PSI minimum. I have an electronic pressure switch (EPS15/99) that will work down to 10 PSI between on and off. There is an Allen Bradley switch (AB836C7A) that I use on systems with really large tanks or water towers. I have systems like this working with as little as 2 PSI between on and off like 48/50.

It is much easier to just use a smaller tank. With a CSV and a 4.5 gallon size tank, the 1 gallon in the tank will be used up quickly. This means a regular pressure switch will drop form 50 to 30, the pump will start, and the CSV will be holding a steady 40 PSI before you can get the temp adjusted in the shower.

Pumps don't usually give any warning before they quit completely. Most people are 3-4 minutes into a 3 GPM shower when the water suddenly shuts off. This gives you just enough time to get all lathered up before you run out of water. As a pump installer I don't know how many calls I got from angry customers who were still standing in the shower with soap in thir eyes when they called me. This is just one more good reason for the smaller tank. That way you can be sure the pump is running before you step in the shower and you won't be all lathered up and run out of water.

Either way a CSV holding a steady and constant pressure will make shower pressure much stronger. I laugh when people tell me they almost no longer need soap in the shower as the constant pressure will just blast the dirt off of them, but it is not far from the truth.
 

JRC3

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So I dropped my switch pressure down to 33-50 and my showers suck. LOL The low pressure is bad enough but every time the pump cycles and the pressure rises, my shower valve's anti-scald adjust and drops off a degree in temp...Could be my tankless heater, but I think it's the valve because the pressure seems to drop off a fraction with every cycle and never completely comes back up as strong as the cycle before it. I bumped my tankless up to 140 from 120 to get more mixed volume, but I don't like the hot water that hot.

Anyways, I just ordered a CSV1A. Can't wait to get it and install it. I saw that the some 2 post pressure switch's differential are adjustable between 15 and 3o psi so I went a little further and tried one cycle with mine at about 12 psi (35 cut in - 47 cut out). I only did it once because of the short cycle so we'll see what it does when the new valve is installed and I can play around. Who knows, tolerances may change and whatnot and it may not work over time.

After that I'll have to play with the pre-charge on my 46G pressure tank to get the most draw-down.
 

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I don't think you should worry about the drawdown given that you would like higher pressure. Why did you widen the separation of cut-on and cut-off pressures?
 

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35/47 is 12 PSI differential. which is more narrow than the normal 20 PSI differential. This is OK, but as you noticed the pump will cycle much more because you are basically only using 1/2 of the tank. If you have a large tank you will want to leave it at 35/47 with the CSV set at about 42-45. If you have a small tank you won't notice the wide bandwidth because it happens very quickly.

If you have a submersible you can probably turn the pressure up to say 48/60 with the CSV set at 55, which would make for even stronger shower pressure.
 

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I'll probably set the cut-off at 50, that's where the original switch was set. Being unsure of the condition and probable past abuse of the pump I'm not comfortable going up to 60. Maybe it doesn't matter between 50 and 60 and I'm just showing my ignorance/inexperience.

Will the lower cut-off help the pump last longer? I'm most concerned about the pump and motor, but also the pipe and pit-less adapter. Like I stated earlier, there were 4-7 people in this house and it had a water-logged 20g and and an old 10g pressure tank sitting next to it. The well produces 10 gpm. It had sat for two years so freezing may've killed the 20g that had been in use.

I don't think you should worry about the drawdown given that you would like higher pressure. Why did you widen the separation of cut-on and cut-off pressures?

Sorry, my writing can be a bit confusing. I didn't really widen it as much as I set it back to where it was before I played around...I played with adjusting the differential by setting the cut-on (up) and cut-off (down), at the same time. This also made it easir to remember the number of turns to get it back where it was. I also felt it kept the cut-in closer to the pre-charge psi. Like I said, this was just for a very quick test of the switch's differential.

Thanks again, guys.
 

JRC3

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The valve was delivered today. Hopefully install it this weekend.
 

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JRC3

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OK Finally got the CSV1A installed this afternoon.

Pressure switch set to 40-53
CSV set to 50
44 gal pressure tank draw-down 5 gallons
With no water running I get a 1 minute pump run-time.

With the pump running and an open faucet flowing at 2.5 gpm, and the CSV flowing at 50 psi, the psi before the csv stays at about 73 psi. I'm guessing that is normal and I actually thought it might be a little higher, I didn't know what to expect and I'm glad it's not. I'm guessing that higher pressure shouldn't hurt the pipe or pump down the hole.

My PT precharge is 38 and I wonder if it were set it a little lower if i'd get more volume on the drawdown?

Pics are with pump running and water flowing.
 

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Valveman

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73 PSI is actually pretty low. Your pump doesn't build much pressure. It is more common to see 100-150 PSI on the inlet side of the CSV. And no that pressure doesn't hurt anything. On the contrary it reduces the amps draw to the motor and makes it run cooler and last longer. But a pump that can only build 73 PSI is fine with a CSV, as long as the pressure switch shuts off the pump at 53 PSI as you have it set.

No reducing the air charge in the tank will not give you more draw down, it will give you less draw down. Widening the band between on and off will give you more draw down. But with a CSV you don't need more draw down. On the old pressure tank only systems, draw down is important to allow the pump to cool down for a minute or two before it restarts. This is because it is cycling on and off the entire time you are using water.

With a CSV the pump will not shut off until you are finished using water, so even with a little 4.5 gallon size tank (1 gallon draw) the pump has plenty of time to cool down before the next time you use any water. You didn't need that large a tank to start with, and you don't need more draw down. The more draw down you have the longer the system will be at low pressure (40 PSI) before the pump starts and the CSV starts delivering the strong constant 50 PSI that you will quickly learn to like. With the CSV you will find yourself waiting for the draw down to be used up and the pump to start before getting in the shower, because then the pressure will be so much stronger.
 

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73 PSI is actually pretty low. Your pump doesn't build much pressure. It is more common to see 100-150 PSI on the inlet side of the CSV. And no that pressure doesn't hurt anything. On the contrary it reduces the amps draw to the motor and makes it run cooler and last longer. But a pump that can only build 73 PSI is fine with a CSV, as long as the pressure switch shuts off the pump at 53 PSI as you have it set.
Could this mean that my pump is just worn out? It did build more pressure with a higher csv setting but I didn't try to max it out or anything.


No reducing the air charge in the tank will not give you more draw down, it will give you less draw down.
I'm not quite sure how to put this...But lowering the precharge (to 31 psi) to match match my 53psi cut-off pressure should increase the drawdown factor, like if my cut-on was 33psi (31 precharge) to match the 53. I think the tank will have more drawdown volume but I'm not sure if that extra volume will actually get to the faucet. Gotta try it.


so even with a little 4.5 gallon size tank (1 gallon draw) You didn't need that large a tank to start with, and you don't need more draw down.
I sorta disagree with the small PT thought. For example, my current 5g drawdown should give me 3-4 toilet flushes per pump cycle...If I only had 1g drawdown then the pump would cycle with each toilet flush. If the toilet is flushed 10x/day then we are talking a difference of 2-3 pump cycles compared to 10. Also, the shower usually has to run for a minute or so to get hot water to the faucet and odds are the pump will kick on and start to increase pressure before you set foot inside.
 

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A 20 gallon tank is a small tank. At 40/53 that tank will only give you about 3 gallons of draw. (2 flushes)
At 33/53 the little 4.5 gallon tank holds about 1.4 gallons of draw. (1 flush)
Now if you widen the band from 40/53 to 33/53 that 20 gallon tank will give about 5 gallons of water. (3 flushes)
Not enough difference to matter. What matters is the pump doesn't cycle when taking a shower or other long term uses.

But if you already have a 20 gallon tank, it will be fine. With 33/55 and a 5 gallon draw on a 2.5 GPM shower head, your shower pressure will just "suck" (your words) for 2 minutes until the pressure drops all the way to 33 so the pump will start. Then in another 30 seconds it will be up to the strong constant 50 PSI from the CSV. But if you already have to wait 2 and a half minutes for hot water to show up to the shower, you wouldn't notice the low pressure from the larger tank after that long.

Also the inlet pressure to the CSV should not have changed. Water level in the well could be deeper maybe, but pumps don't usually wear out gradually like that. It is usually max pressure until the day they die. The most pressure you will see on the inlet of the CSV is at 52 PSI at the tank, just before the pump shuts off at 53.
 

JRC3

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I've confused things by not explaining my post properly, I'm not good explaining in text. First, I have a 44g PT and not a 20g. I am getting about 5g drawdown from that 44g tank with a setting of 40/53. The cut-on is not 33, it is 40...I was saying to set the precharge as if it were 33 so the precharge is more or less set for the cut-off of pressure of 53. Basically set the precharge for the standard 20psi differential. Just thinking how you get more drawdown volume from a 30/50 setting than a 40/60 setting.

A side note, this tank has always seemed to put out a little less volume than what 44g tanks are advertised. At 3o/50 I'd get like 11.5 and at 40/60 I'd get like 9.5 gallons of drawdown. Maybe my cheap gauges read a little off or the bladder relaxes, IDK. Been like that since it was new in 11/2015.

Thanks, again.
 

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Luckily I only use about 60 gallons a day.

It is very common for a pressure tank to hold less than advertised. And I don't know why you are even concerned since you only use 60 gallon per day. Even if the pump cycled on for every gallon used, that would still only be 60 cycles per day. But even with a little 4.5 gallon size tank (1 gallon draw) when using a CSV the pump does not cycle for every gallon used. The CSV makes the pump cycle for each water use, no matter how many gallons that is. So the pump stays on steady (1 cycle each) during two 20 gallon showers. Then it might cycle about 10 times for 20+ toilet flushes, for a grand total of 12 cycles per day.

Even with a 40 gallon tank that holds 10 gallons of water you would get 6 cycles per day. The difference is with the big tank, CSV or not, is every time you use water the pressure will be decreasing from 53 to 33 for each 10 gallons used. And as you said that low pressure "sucks".

With the CSV and small tank the pump would cycle 12 times per day instead of 6. But each use of water would be at a strong constant 50 PSI, which is so much stronger shower pressure than 33 PSI that you probably will no longer need soap.
 

JRC3

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I'm not complaining, I guess I figure a larger PT for fewer cycles and a csv for a steady shower is the best of both worlds. I mean fewer cycles is important, right?

Once the pump gets replaced and then eventually when this 44g tank dies I'll go with a smaller 14 or 20g. Maybe smaller, who knows.
 

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If the tank ain't broke, don't fix it. But when it does break and you switch to a small tank, the pressure will be so much stronger you will wonder what took you so long to make the change.

And yes fewer cycles is best. But those little pumps can handle between 100-300 cycles per day, so the difference between 6, 12, or even 60 cycles per day is not going to make much difference.
 

JRC3

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UPDATE

Ignore most of my BS since I installed the csv. I finally get it, I shouldn't be worrying about cranking the pressure up on my well a little bit. ;)

So I decided to crank my cut-out to 60psi and adjust the csv to 56, and guess what? The pressure before the csv stayed the same psi.

My cut-in is at 45 so I get my 1 minute of minimal runtime. Gonna raise my precharge to 42 and be done.

Using the flow meter on my Fleck 7000 my shower always fluctuated between 2.2-2.5 and now it stays at 2.7gpm. I know it's not the most accurate, but it is a good indicator of the difference in flow. The difference between 2.2-2.5 doesn't sound like much but it is in the shower. My guess, the extra flow is only beneficially to cool the pump.

Thanks again
 
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Valveman

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The pump/motor really only needs about 2/10's of a GPM to stay cool. The CSV has a 1 GPM minimum, which is a safety factor of about 5 times the amount needed to cool the pump/motor.

The extra flow in the shower is because of the strong constant pressure from the CSV. The stronger the pressure, the more flow gets through that little 2.5 GPM flow restrictor in the shower head, which makes the shower pressure stronger.

People who have never experienced constant pressure just think the pressure fluctuating in the shower is normal. But after they experience constant pressure,they never go back. :)
 

JRC3

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I always yank shower head flow restrictors but I'm sure my shower valve also restricts. I'm sure a shower head restrictor would mask the up and down pressure of a pump cycling. But all than means is you never fully experience the high side, this could be why most people don't notice the pressure swings so much. I yanked it out of my kitchen sink too. Hey, it's my private water so I'll use all I want. LOL

Also, I have a booster pump on my RO drinking water, if I'd known I was gonna have 45 psi I probably woud've gone with a permeate pump.
 
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