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".