Use of waterlogged pressure tank

[citytransplant]

Greetings and happy 2023 to all.

When we moved into our semi-rural cottage in 2005 our water was supplied by two separate systems. System A supplied cold water (high in iron) drawn from a shallow well by a 1/3 HP jet pump (pressure tank and pump manufactured in 1988). Hot water (System B) consisted of soft rainwater collected from roof into a large open cistern in cellar. The water from cistern was pumped into water heater by a similarly sized pump. The hot water was used in bath, laundry, and kitchen. In principle this worked perfectly. My hair was soft as silk.

After a few years it became clear however that the cistern was a repository for rodents, bird droppings rinsed from roof, and other contaminants. The standing water triggered a moisture issue that contributed to additional problems. I decided to discontinue the dual-system and tie the water heater into System A. We were able to pay for associated labor from savings in anti-diarrheal medication (just kidding).

It appears the pressure tank bladder in System A has finally failed. My question is: can I swap out the 35 year old pump and waterlogged tank, replace it with pump and tank from System B and then connect the waterlogged tank downstream from the replacement tank/pump simply to add greater capacity to the system?

 

[Roadworthy]

If your tank is water logged it will add no more capacity to the system than an old hot water heater. When the bladder goes the tank is useless as a pressure tank. You may also get bad tastes in your water from the metal in the tank reacting to whatever hardness is in the well water. I know - my water was disgusting until I replaced the pressure tank. Now it's as good as new. I do have a couple eighty gallon pressure tanks by the driveway if you're interested. You will have to drain the failed tank before moving it and is WILL be heavy unless you do so.

 

[citytransplant]

Thanks for reply @Roadworthy
I realize the tank won't offer pressure as that will be the job of the "upstream" tank. I envision the waterlogged tank to act exactly like the old water heater that you referenced. That is: adding additional storage capacity to the system so as to reduce the frequency of pump cycling.
What's wrong with my logic, if anything?

 

[Larry Caldwell]

If the bladder goes bad you can convert the tank to an old traditional captive air tank by adding air. At least you can't over-fill it. If you add too much air, the excess will just bubble out into the lines. It's a temporary fix to keep the pump from short cycling.

 

[Avenger]

Yeah, if the pressure tank is blown, its done.

I bought my home in 2014, and it had a huge pressure tank in the basement mechanical room. After about 3 months of living there, the tank blew and filled up with water. I had to drain it and find a replacement asap! Fortunately, Home Depot had a large (but smaller) tank in stock. That tank was used for about a year until we put in our cistern. The company that installed the cistern pushed me in the direction of a Subdrive Constant Pressure System.

Subdrive Constant Pressure System - National Water Service

SubDrive Utility offers simplified constant pressure solutions for compatible submersible well water pumps. Click here for more information on the subdrive

nationalwaterservice.com

This very small pressure tank sits inside my cistern, just above the water level. It provides a constant 65psi to the house. No more well pump kicking on at 45 psi and kicking off at 65. I hated the pressure ups and downs! This thing is awesome!

However, we did leave the larger pressure tank in place in the house. It acts like a shock absorber for when the pump does kick on. Since 2017 this system has worked very well.

There is a playlist on my YT called Well Project where I show the subdrive unit.

 

[Larry Caldwell]

Thanks for reply @Roadworthy
I realize the tank won't offer pressure as that will be the job of the "upstream" tank. I envision the waterlogged tank to act exactly like the old water heater that you referenced. That is: adding additional storage capacity to the system so as to reduce the frequency of pump cycling.
What's wrong with my logic, if anything?

Water is not compressible. You will gain nothing by having the old waterlogged tank in the line. Adding air will be a temp fix.

 

[Halftrack]

Seriously consider having your "shallow" well water tested for contamination, nitrites, nitrates, iron and lime. Your local health department will know who can test your water. Check with your neighbors to see how deep their wells are compared to yours and whether they are dealing with iron or lime. Then consider if it's time for a new well and plumbing.

 

[CobyRupert]

The “capacity” of your system is a function of how much the air above the water in the sealed ballast tank expands and contracts during the “pump up” and “drawn down” cycles.
So, without additional air (or an air bladder) above the water in a sealed tank, there’s nothing pushing this water out of the tank during “drawn down” cycles.

…but if the tank’s air bladder is “bad”, the trapped air eventually dissolves into the water and there’s no volume of compressed air to push the water out anymore. Or the air volume is so little, you can only draw a gallon or two of water before the pressure drops fast and the pump must start….but quickly replaced the small volume of watered drawn, pressure rises and pump quickly shuts off (aka: “short cycling”).

My mom just replaced her “air-over-water” ballast tank. It probably was 70+ years old. It never had a bladder. Strictly air over water in a sealed tank.
To counter the air dissolving into the water with no bladder, an “air make-up valve (also called an “air volume control valve”) is used on the tank.
Every time the jet pump starts, a ~1/8” tube from the jet pump sends a pulse of water to the valve. This pulse pushes on a diaphragm in the valve and the other side of the diaphragm send a gulp of air back into the ballast tank, ideally making up lost air that has dissolved into the water since the last time the pump started.

 

[turnkey4099]

Water is not compressible. You will gain nothing by having the old waterlogged tank in the line. Adding air will be a temp fix.

late to the feast but if it hasn't been mentioned. It will add storage but do nothing for frequency of pump cycle.

 

[citytransplant]

Re: water testing and neighbors...

Our well sits 50' from a livestock barn in one direction and 50' from a leaky septic tank in the other. What could possibly go wrong?

I appreciate your concern @Halftrack I really do but I live in New York State where if you fart too frequently you risk being cited for an air quality violation. I've learned the hard way to keep local health department and the State Environmental Conservation people at a distance. Heck, even neighbors invite unnecessary scrutiny. Our goats and chickens are evident from the road and occasionally folks driving and walking by ask to be invited onto the property to get a hands-on look. Everything was peachy at the unofficial petting zoo until one day a neighbor noticed a dead chicken tossed aside that I had yet to add to the compost pile. Later that day the lady from the State Dept of Agriculture showed up due to an "anonymous" call regarding an avian flu outbreak. She and my wife had a good laugh, but still.

I've been drinking water from that well and worse (read what was in my cistern) for 18 years. I fear sending my water off to be tested only to have another government bureaucrat show up at my door looking to "help." I was one for almost 30 years and you want less of what I had to offer, not more.

As my gal often says when the old man begins his groveling for.. err.. a lil attention: "no thanks, I'm good".

 

[citytransplant]

While I'm on subject of government bureaucrats... I trade NYS made knives as a hobby. I spent a few hrs. one Saturday at the kitchen table of the County Health Dept. guy in charge of inspecting septic systems. He had quite a collection of Camillus Cutlery Co knives for sale and I spent the afternoon pricing them so as to make an offer. We had an enjoyable time together talking knives and such.

I see him in the elevator at work (I was a "county worker" too) some time later and I tell him that I think a line in my drainfield must have failed and asked him for a possible solution. He responded with "I will come out and have a look."

Me thinks he's going to swing by on his way home from the office all unofficial-like. Instead he shows up in the middle of workday in County vehicle, clipboard in hand.

Had I not enlisted a septic guy who knew his way around the drainfield (read a farmer with a backhoe and a way with words) that elevator ride could've cost me tens of thousands. In hindsight I might've avoided the situation all together had I agreed to pay his inflated ask price for the knives.

 

[citytransplant]

I just had the "A HA" moment !!!

Kind of like when I first learned where babies came from and that Santa Claus thing the adults were trying to sell me.

It will take the same amount of time for the pressure to drop from cut-out (40 lbs in the case of my system) to cut-in (20 lbs) no matter the volume of water in the pressure tank(s). Therefore adding an additional non-pressurized tank beyond the operable pressure tank does not reduce number of cycles per hour, day, etc.

Man, I'm slow.
But I sure look damn good.

 

[kf4uda]

Cut that tank in half long ways and make a couple of feeding troughs for your goats. It will continue to serve you

 

[citytransplant]

Anything to distract them from chewing wires & hoses on my tractor.

 

[groundcover]

Or cut the top off and build a counter weight for the tractor !

 

[AnotherBueller]

If the bladder goes bad you can convert the tank to an old traditional captive air tank by adding air. At least you can't over-fill it. If you add too much air, the excess will just bubble out into the lines. It's a temporary fix to keep the pump from short cycling.

If you add air to a non-bladder water tank it will work untill the air becomes water logged (10% humidity), then it doesn't work and you'll have to open the high point at the top of the tank and let water fill it completely, drain the tank to let in dry air, close the top vent and refill the tank. What you've described is a non-bladder device to stop water hammer. Depending on the size they'll only last a few years and then you get water hammer again.
The only use you will realy get is as a water tempering tank to raise water from 55-60 degrees F to what ever to room is (ie" cooling the room)

 

[Valveman]

A water logged bladder tank will not add a volume of water to anything. Best to cut it in half and use as a watering trough as was suggested. While you are replacing your pressure tank it would be good to learn what causes the bladders to fail and make the tank waterlogged. Cycling on and off of the pump makes the bladder go up and down with each pump cycle. This is like bending a wire back and forth until it breaks. Eliminating the cycling of the pump not only makes the tank and everything else in a pump system last longer, but also delivers strong constant pressure to the house.

There are two ways to eliminate pump cycling. You can use a variable speed drive or VFD, like the Subdrive someone mentioned. These systems vary the speed of the pump to keep it from cycling on and off. However, these type systems are expensive and don't last very long, which is why they are so popular and promoted so heavily by some pump installers.

The other way, and best way to eliminate pump cycling is with a simple Cycle Stop Valve. These valves vary the flow from the pump without varying the pump speed, which eliminates cycling and delivers strong constant pressure to the house. With a Cycle Stop Valve a little 4.5 gallon size pressure tank is all that is needed, as the water is perfectly controlled and goes right past the tank anyway. The system doesn't know if it is a 1 gallon or a million gallon size pressure tank.

The variable speed type systems also use very small pressure tanks. But when these complicated and expensive VFD systems start giving problems and costing more money, many times they are replaced with Cycle Stop Valves.

 

[Larry Caldwell]

If you add air to a non-bladder water tank it will work untill the air becomes water logged (10% humidity), then it doesn't work and you'll have to open the high point at the top of the tank and let water fill it completely, drain the tank to let in dry air, close the top vent and refill the tank. What you've described is a non-bladder device to stop water hammer. Depending on the size they'll only last a few years and then you get water hammer again.
The only use you will realy get is as a water tempering tank to raise water from 55-60 degrees F to what ever to room is (ie" cooling the room)

Humid air is a real problem, just like the stale air in car tires. You have to deflate the tires and refill them with fresh air or your ride will suffer.

 

[Larry Caldwell]

The most common reason tank bladders fail is freeze damage.

 

[Valveman]

Bladders in tanks fail even more frequently in Mexico and Central America where it never freezes. That is because they commonly use much smaller pressure tanks than normal, which increases pump cycling and the number of times the bladder in the tank goes up and down.

Even in colder climates freeze damage to a pressure tank is rare. Being the tank is the largest part of the water system it takes MUCH longer to freeze than the pipe to/from the tank or the little nipple to the pressure switch. I have thawed out and repaired many frozen pump systems. When I get the frozen lines cut loose from the tank, the water in the tank is still liquid, squirts out, and gets me wet.

In the same way it is hard to freeze a cistern or storage tank because it takes a long time to freeze several hundred gallons of water. But the pipe to/from the cistern can freeze in a few minutes below 32 degrees.