Adjust my pressure switch or install my CSV?

[k-n]

My system is 3HP well pump that pumps to a 2500 gallon cistern. From the cistern I go to a goulds J10s 1HP electric. My original plan was to put a CSV in to keep the goulds running at 50PSI constant. My issue is I have an 86 gallon AO Smith pressure tank and the CSV is supposedly supposed to be on a really small tank to prevent low flow issues. I was a bit over my head on doing this so I paid my well company to do this install. He didn't like the CSV at all and didn't want any part of it so it's set up as a standard 40/60 pressure switch. I know exactly how the system works, is wired, etc., but making sure it was all done quickly was key as I didn't have time to research the 3-float alarm system.

I'm not happy with a 40-60 delta. It is noticeable using the shower/tub when it hits the low/high extremes and I'd like to narrow it a bit.

Option A is put in the CSV and try to make it work with the big pressure tank and/or get a small pressure tank.

Option B is to adjust my range on the goulds pressure switch to about 45-60 and see if I can live with it.

Any suggestions on the best route? I already bought the cycle stop valve for 50psi as the Goulds J10s has plenty of flow at 50 PSI for my household needs. It's rated at 16.6GPM with 5' of lift. I have no lift and, in fact, have positive pressure as the goulds is pulling from the bottom of the 2500 gallon cistern so there's a good bit of pressure from elevated water.

 

[Reach4]

Option B is to adjust my range on the goulds pressure switch to about 45-60 and see if I can live with it.

If you turn the nut on the small spring CCW enough to take all of the compression of of that spring, you might go to 40/58. Then you can raise both cut-in and cut-out by turning the nut on the big spring CW.

 

[Sponsor]

 

[k-n]

If you turn the nut on the small spring CCW enough to take all of the compression of of that spring, you might go to 40/58. Then you can raise both cut-in and cut-out by turning the nut on the big spring CW.

According to the little manual I got, it's about 2.8PSI per full revolution on both nuts with 3 1/2 full turns max for a max 10 psi change. If I go this route, I'd raise the range to 45/65 and back down the cutoff about 1.75 turns to get back to 60. Of course I'll need to ajust the PSI in the tank to about 43 PSI.

 

[Reach4]

According to the little manual I got, it's about 2.8PSI per full revolution on both nuts with 3 1/2 full turns max for a max 10 psi change. If I go this route, I'd raise the range to 45/65 and back down the cutoff about 1.75 turns to get back to 60. Of course I'll need to ajust the PSI in the tank to about 43 PSI.

Yep, good starting point, but you will use pressure gauges for the real numbers.

To compare the calibration of your water pressure gauge and air pressure gauge, the water and air pressure will be about the same at intermediate water pressures, such as 5 to 10 psi above the air precharge preessure. Actually close at all normal pressures, but I wonder if there could be some diaphragm tension near cutoff.

Small factors in actual difference of diaphragm tension and altitude difference between the top of the diaphragm and the water pressure gauge altitude (gauge typically low) work to cancel each other. So, in practice, saying simply "same" works.

If you ever replace that well pump, I expect a lower-HP pump will be a better fit if you don't have really high water usage for long periods. Smaller pump will reduce cycling on that pump.

 

[Bannerman]

Reducing the delta on the pressure switch will result in the Goulds pump to cycle more frequently which will likely reduce its lifespan.

Your existing 86 gallon tank will hold approx 22 gallons water between 40-60 psi. While that large tank may be utilized with a CSV, the entire 22 gallons will need to be consumed before the pump is activated. Once activated at 40 psi, the pump will run at its maximum pumping rate to supply whatever water is being consumed + add 11 gallons back into the pressure tank before the CSV will regulate the pressure to 50 psi.

When a smaller tank is used with a CSV, less water will need to be consumed before the pump becomes activated. If an 8-gallon tank is used, only ~2 gallons will be consumed before the pump is activated and only 1 gallon will be added back into the tank before the CSV regulates the flow at 50 psi. When a smaller tank is used, the pressure will often be stable at 50 psi in the time from turning the shower ON, to when the person actually enters the shower.

 

[VAWellDriller]

Using what you have, you can install the csv, let a bunch of air out of the tank and make it act more like a small tank.

You could also set the switch really high....like 50/70...still use the csv to prevent cycling as it only really cares about the cut off point. You might not mind the delta if pressure was always high....just need to make sure pump is capable of reaching the cut off point.

 

[Valveman]

He didn't like the CSV at all and didn't want any part of it.

Lol! Been doing this for 28 years now. I can tell you what the well guy/plumber said. "That back pressure is gonna burn up your GD pump. That little tank will cause the pump to cycle itself to death, especially if you have a leak. Pump company will void warranty if you use a Cycle Stop Valve." After all these years I have no patience with a pump man or plumber who doesn't know better. That is a load of horse hockey.

Back pressure is good for a pump. Makes it draw lower amps and run cooler. You can't short cycle a pump that is controlled by a Cycle Stop Valve, because the Valve Stops the Cycling. Even with a small leak and the small tank you cannot short cycle a pump when using a Cycle Stop Valve.

Here is a video/audio of a pump man saying just such things. Show this to your plumber/ well guy and tell him this is how foolish he looks. Lol! He is trying to keep you from having the MOST beneficial system you can for your pump system. The smart ones do this because they understand the CSV will make your pump last 30 years. The rest of them are just idiots and there is no way to sugar coat it.

 

[Valveman]

I'm not happy with a 40-60 delta. It is noticeable using the shower/tub when it hits the low/high extremes and I'd like to narrow it a bit.

You have the solution in your hand, which is the Cycle Stop Valve. I assume you have the CSV125 set for 50 PSI and has a 3 GPM bypass. This valve will work great with your J10S pump. Because of the low back pressure from a jet pump, the 3 GPM bypass is needed and will allow about 1 GPM minimum flow without cycling.

However, you will not see the strong constant 50 PSI from the CSV until the tank is empty and the pump has started. As has been said your 80 gallon tank holds about 22 gallons of water. With a 2.5 GPM shower you will be watching the pressure fall for nearly 10 minutes. Once the pump starts you will finally see the strong constant pressure you want.

With the CSV125-50 there is no adjustment, it is set at 50 PSI. To make it work with any size tank the pressure switch much be adjusted according to the tank size. The CSV will fill the tank at 1 GPM from 50 PSI up. Running a 50/70 pressure switch would make it take 22 minutes to fill the tank after you stop using water. We only want the pump to run filling the tank for 2-3 minutes. So, with an 80 gallon size tank the pressure switch will need to be adjusted to about 33/53.

Loosening the small adjustment screw in the pressure switch as much as possible will usually get it down to about 17 PSI delta. So, off at 53 would mean on at 36 PSI. But you are still not going to like waiting on it to get down to 36 before the pump starts. You can also reduce the air charge in the tank to like 20 PSI. Although this will cause the diaphragm to over-stretch a bit, with the CSV it won't stretch very many times because it is not cycling on/off constantly, so the diaphragm will last a long time. This is actually how the tank manufacturer says to operate the tank, so you have some water stored for a power outage. Reducing the air in the tank to 20 PSI will actually increase the gallons stored in the tank to about 30 gallons. However, it will decrease the drawdown amount as the pressure drops from 53 down to 36 PSI to about 15 gallons instead of 22. The other 15 gallons in the tank will not come out unless the power goes off and the pressure falls from 36 down to 20 PSI. In this way you have 15 gallons after the power goes off. With the standard 2 PSI below cut in air charge in the tank, the tank is empty about the time the pump should start, and you do not have any water stored for power outages, which is normal with a bladder/diaphragm style tank.

What you really need to do is replace that 80 gallon tank with a 4.5 or a 10 gallon size tank, so you get the constant pressure you want without having to wait for it. Then you could take that tank back to the pump guy who has no idea what he is doing and get your money back. Maybe it will force him to figure out how pumps and CSV's work. What he is doing is no different than if you went to purchase a new car, and the dealer says you can't have an automatic. You must live with it manually switching between 40 and 60 all the time, as those automatic transmission Cycle Stop Valves are bad for the motor. You wouldn't put up with a car dealer who wouldn't sell you a car with an automatic transmission, and you shouldn't put up with a pump guy who won't let you put a CSV on your pump top make it work like an automatic transmission. I am sure when the automatic transmission first came out mechanics were unsure of it as well. But mechanics finally figured out it was a good thing, and pump guys should figure this out about the CSV as well, or they are not very good pump guys.

 

[k-n]

Thank you! I typed up a long reply, submitted, and it went into a black hole. Bottom line is I'll get a small tank and some pix and come back for more help. Thank you!

This is what I ordered and have on hand:

1x CSV125-1 Cycle Stop Valve - 50 psi

 

[Valveman]

I hate it when I loose what I typed. But it was usually me hitting the wrong button. On long replies I use Word and copy past so I don't loose my original. For the Jet pump the CSV125-3 would have been best. But the -1 will work. Just needs a little more care in adjusting the pressure switch or the -1 on a jet pump will take a long time to fill the big pressure tank. You will be glad you went with the CSV as an automatic transmission for your pump as it is much better than the old pressure tank only stick shift.