Pressure tank problem?

[LLigetfa]

I tried messing with the switch differential (small) screw before on a new switch and learned I won't do it again. Ended up replacing the switch after I got the first one totally out of whack.

With the small nut unturned until the spring is loose, you will have the smallest possible differential, so it is not hard to get back to that setting. You can even completely remove the nut and small spring as its intention is to increase the differential. Underneath the small spring seat, there might be a few shim washers that determine the starting position at which the small spring starts to work.

 

[LLigetfa]

The system pressure will need to drop to the cut-in pressure regardless of the CSV's regulated pressure setting so increasing the CSV adjustment in of itself will not result in any delay.

The CSV is set to a specific desired pressure. If 43 PSI is desired, then the time between that and the kick-in pressure is less than if the desired pressure is raised. After you get used to having the higher desired pressure, you do notice the longer time before you get it.

 

[Sponsor]

 

[Bannerman]

The CSV only regulates the pressure and flow rate delivered from the pump.

Regardless of whether the CSV has been calibrated for 35, 40, 43, 45 or 48 psi, the system pressure will need to drop to 30 psi before the pump is activated. How fast the pressure will drop to 30 psi will be conditional on how fast water is flowing to the faucet(s) in use.

 

[Sarg]

Adjustment made and hovering at about 47 psi. during usage.
Perfect.

 

[Bannerman]

hovering at about 47 psi.

After stopping water usage, how long does the pump need to run before it is shut down at 50 psi?

 

[Sarg]

After stopping water usage, how long does the pump need to run before it is shut down at 50 psi?

That measurement will have to wait til she takes another shower.

I'll be very curious if CDN's issues mirror my prior problems.

 

[LLigetfa]

The CSV only regulates the pressure and flow rate delivered from the pump.

Regardless of whether the CSV has been calibrated for 35, 40, 43, 45 or 48 psi, the system pressure will need to drop to 30 psi before the pump is activated. How fast the pressure will drop to 30 psi will be conditional on how fast water is flowing to the faucet(s) in use.

You're not telling me anything I don't already know.

Let's say the PS is set to 30/50 and the CSV to 43. Let's also assume no other water use while showering. During a shower, you turn off the water to soap up, and the pump reaches cut-off. When you turn the water back on, you will enjoy the pressure from 50 down to 43 and then suffer the lower pressure down to 30 before the pump turns on.

Now let's say the PS is set to 40/60 (10 PSI more than before) and the CSV upped to 45 (2 PSI more). 43 was acceptable before but 45 is a little better. When you turn the water back on, the new 45 PSI you have grown accustomed to is not that far off from the 40 PSI cut-in. However, if you left the PS at 30/50, the time it takes for the pump to come on will be longer.

Also, when you raise the PS on/off values, it reduces the tank's drawdown, so a smaller drawdown means the pump will come on sooner. All this of course is predicated on the pump not deadheading at or near 60 PSI.

 

[Sarg]

There are folks that turn off the shower flow to "soap up" ????? ............ Who knew.

 

[Reach4]

There are folks that turn off the shower flow to "soap up" ????? ............ Who knew.

https://en.wikipedia.org/wiki/Navy_shower

 

[LLigetfa]

I use less water to shower than what my drawdown capacity is so there is a chance the pump won't even run.

 

[Sarg]

Truly thrifty.
We have to manually set our mix.

 

[cdn97986]

Thanks for everyone's replies, learning a lot here. That said, I still do not have a definitive answer as to why my pump is filling my 20 gal pressure tank w/ a 6.2 gal drawdown in 26 seconds. I tinkered with the pressure switch, and the tube is clear, and it responds to adjustments as it should by turning the nuts. When returning to where it was originally, the pump is still kicking on at 30 psi, and off at 50 as it should. I re-drained the system to get the water pressure to 0, and the pressure tank is still right on at 28 psi (been 2-3 weeks since adding air now). Drawdown was still 5.25 gallons, so about a gallon short. Shook the tank again when empty, and still no water sloshing. Pressure at all faucets is great (as usual), and outside of the short fill time, system is working great. I honestly do not know what my cycle time was before repairing the check valve, but I don't see why it would have changed now. And I have lived in my house for ~10 years, so I doubt that a pump cycling this way would last that long, and who knows how long it has been in the well before that (house was built in 1989). So the math doesn't lie, it looks like my pump is producing ~11 gpm, which would mean I would need a 11+ gallon drawdown capacity to keep the minimum 1 minute run time, so looking at a 40+ gallon tank. As I mentioned in my original post, I have no info on my pump. My Amtrol 20 gallon pressure tank is original to the house and is dated 1989, so well undersized for 30+ yrs. I've started shopping around for a 40 gal replacement. I can go ~ 5-6 feet high, but not much more that 15-16 inches wide due to a narrow area where the tank needs to fit. CSV sounds interesting, but not 100% sure that is what I'd want to go with here with a tiny tank. I'm stumped...anything else to check before replacing the tank with a bigger one?

 

[Reach4]

Thanks for everyone's replies, learning a lot here. That said, I still do not have a definitive answer as to why my pump is filling my 20 gal pressure tank w/ a 6.2 gal drawdown in 26 seconds.

I thought it was clear that the practical drawdown was about 5 gallons, and that your pump was filling that tank at something over 10 gpm. You laid that out in post #1. What is mysterious?

You could use the CSV with your 2o gallon tank.

Alternatively, you could put two tanks in parallel, with a 1 inch diameter short pipe path between them.

 

[cdn97986]

The mystery is how my pump has survived this long with an undersized tank and short cycle times. From all I have read, this should have killed it long ago. We don't use a ton of water, maybe I'm just lucky?

 

[Bannerman]

not 100% sure that is what I'd want to go with here with a tiny tank.

The purpose of a pressure tank is to reduce cycling. Since your pump is delivering 11 GPM, unless 11 GPM is flowing each time water is needed, the pump will continue to cycle, even if a 500-gallon tank was used.

A CSV changes how the pump will deliver water as it will vary the pump's output to match the actual flow rate being used. In so doing, the CSV will prevent the pump from cycling as long as more than 1 GPM is being drawn. Because 1 GPM is the CSV's minimum flow rate, the pressure tank will be filled at 1-GPM so even a 4-gallon tank with 1-gallon drawdown capacity will provide 60 seconds minimum run time.

Because the CSV functions by regulating the downstream pressure, an additional benefit of using a small pressure tank will be, only a minimal quantity of water use will cause the pump to become activated, resulting in constant pressure for the remaining time water is being consumed.

 

[Reach4]

The mystery is how my pump has survived this long with an undersized tank and short cycle times. From all I have read, this should have killed it long ago. We don't use a ton of water, maybe I'm just lucky?

You may not have a whole lot of irrigation. Good Franklin motor on your pump.

 

[cdn97986]

The purpose of a pressure tank is to reduce cycling. Since your pump is delivering 11 GPM, unless 11 GPM is flowing each time water is needed, the pump will continue to cycle, even if a 500-gallon tank was used.

A CSV changes how the pump will deliver water as it will vary the pump's output to match the actual flow rate being used. In so doing, the CSV will prevent the pump from cycling as long as more than 1 GPM is being drawn. Because 1 GPM is the CSV's minimum flow rate, the pressure tank will be filled at 1-GPM so even a 4-gallon tank with 1-gallon drawdown capacity will provide 60 seconds minimum run time.

Because the CSV functions by regulating the downstream pressure, an additional benefit of using a small pressure tank will be, only a minimal quantity of water use will cause the pump to become activated, resulting in constant pressure for the remaining time water is being consumed.

Thanks for the additional info on CSV, it's clear to me technically the tank requirements for the CSV. I lose power at my home several times a year, some times for a couple of days, so having a few gallons of water in reserve for these situations is a must for me. So I would want probably at least a 20 gal tank w/ 6 gals of drawdown to address this. For what I was pricing out, the CSV + a 20 gal tank is about the same as a 40 gal tank without the CSV. Just need to convince myself what is the better option for us.

 

[Valveman]

You have almost no chance that a 20 gallon tank will have 5 gallons of water in it when the power goes off. With a 40/60 switch, the tank is full at 60 and basically empty at 41 PSI. Unless you knew the power was going off and cycled the pump to top off the tank before bed, you cannot count of having any water stored in a pressure tank. I keep a 5 gallon bottle of water in the closet, and a generator for the pump for when power is off for any length of time. They make storage tank systems that use a 12V RV pump or air compressor to force water out during power outages. But a pressure tank only holds 25% water and is designed to reduce pump cycling, not to store water.

Although the CSV will work with any size tank you want, larger tanks are just a waste of money and space. Larger tanks also make it take longer to see the strong constant pressure from the CSV.

The big tank manufacturers will recommend an 80 gallon tank with a 20 PSI air charge to store water for power outages. This can give you a few gallons of water even when the pressure is at 41 after the power goes off. However, the lower air charge will greatly reduce the draw down volume of the tank between 40 and 60 as well as over-stretch the tank diaphragm and shorten its life.

Here are a few hundred 5 star reviews, some as old as 1993, that should help convince you the CSV is a better option.
https://cyclestopvalves.com/pages/reviews

 

[LLigetfa]

You have almost no chance that a 20 gallon tank will have 5 gallons of water in it when the power goes off. With a 40/60 switch, the tank is full at 60 and basically empty at 41 PSI. Unless you knew the power was going off and cycled the pump to top off the tank before bed, you cannot count of having any water stored in a pressure tank.

I agree. If my power were to go out now, there would be very little drawdown to rely on if I had captive air tanks. My tanks are hydro-pneumatic and my second inline tank is a contact tank with more water/less air so I always have water in reserve. Also the air in a HP tank will move forward and displace most of the water in my iron filter and softener media tanks giving me even more reserve. My PS is 38/60.

 

[Valveman]

You can attach a 12V air compressor to a hydro-pneumatic tank and force out quite a bit of water after a power outage. Usually about 1/3rd of a hydro tank is wasted space. But that space is full of water if you have a way to force it out during a power outage.