pressure tank size

[ugabulldog]

Apparently an air over water tank needs to be about twice as large as a bladder tank for the same amount of drawdown, is this correct? Also, can an air over water tank be used without an air injector, and without any additonal valves, air control etc... as long as i add air every couple of months when it gets low?

 

[Ballvalve]

Yes, and you can pump up that air charge to the pumps cut in pressure or a bit below, and get double the drawdown until the air is absorbed again.

They used to make a tank with a floating disc inside to greatly stop air being absorbed. I have one that must be 25 years old. Use an oiless compressor.

 

[Sponsor]

 

[ugabulldog]

I am getting different opinions from people I talk with, like I need a bleeder valve in well for this set-up to work, is this not true?? thanks

 

[Ballvalve]

If you do not get a lot of freezing, you can do your bleeder above ground in the pumphouse. Even better, as you can maintain it. You can even adjust the air charge by adjusting the placement of the check valve and schrader valve between the bleeder. If you get it right, you do not need an air release valve.

I have 3 motley tanks in a row, and stopped charging them when I realized the water had enough air "in" it to keep the charge. Fooling with plain tanks is more art than science.

here is a start; http://www.inspectapedia.com/water/Bad-Water-Tank.htm

But again, if you actually DO maintenance, you can use the compressor alone, or hope your well pumps sparkling water.

 

[Valveman]

Actually a “pressurized” air over water tank will supply more draw down than the same size bladder tank. Maintaining a pressurized amount of water in the tank takes a dedicated compressor with its own pressure switch and probes mounted inside the tank. This is a complicated set up and I have only seen it on very large municipal type systems.

Sure you can just air up a tank occasionally and everything will be fine. Most people don’t have enough air in their water to maintain the correct amount of air in a tank. Usually it is just the opposite. The air will mix with the water and goes out the sprinklers or showers until the tank is waterlogged. Then if you forget to air up the tank just one time, you will notice the lights flickering funny one night, and wake up to no water and a burned up pump in the morning.

There are all kinds of automatic air injection systems. The bleeder orifice you mentioned is one of them. Then you have venturi air injectors, and actual dedicated compressor systems. All these things have several moving parts and small holes that can become clogged. Continuous problems with these things are why the bladder tank came to be.

The bladder tank is an improvement to the old air over water type tanks. It maintains the correct amount of air in a bag or bladder, which separates it from the water. In this way the air cannot mix with water and be discharged, and you don’t need any kind of automatic air charge system. The main problem with bladder type tanks is from the bladder failing. The bladder fails from the bending action that happens when the pump is constantly cycled on and off to fill and drain the tank as needed. So all you need is something that stops the pump from cycling on and off to eliminate any problems associated with bladder tanks.

Your water actually comes from the aquifer, reservoir, or cistern, not the pressure tank. Pressure tanks only hold a few gallons of water and its only purpose is to limit the cycling on and off of the pump. So again, if you have something that Stops the Pump from Cycling, (hint, hint) the pressure tank is of little importance. If you have a device that Stops Cycling, you won’t break a bladder even in a small bladder tank. As you can see in the picture to the left, when you have a device that Stops Cycling, even a tank that only holds 1 gallon of water is sufficient for most houses.

The problems of air over water tanks was solved by the bladder tank, and the main problem with bladder tanks is solved by eliminating the cycling.

 

[ugabulldog]

thanks valveman, however the whole reason for going with the air over water tank is the water has time to mix with air before going thru a iron filter, so your set up wouldn't work I don't think.

 

[Valveman]

Well if that’s the case, then you do need a regular air over water type tank. Aerating the water is the only reason to use one of those old style tanks. When you have something like that in the water, your only choice is a standard tank. But you will also need an air maker system. You can’t just leave the same air in that tank, and top it off with a compressor occasionally, or the smelly stuff can’t get out. I would recommend a bleeder orifice in the well, and an Air Volume Control (AVC) in the tank. This way the tank gets some fresh air each time the pump starts, and some of the smelly air will get released through the AVC each time as well.

You can still use a CSV with a standard tank. You just have to use one of the brass bleeder orifices, so the higher pressure won’t pop it out, like it would a rubber bleeder. With the CSV, you can use a smaller air over water tank, and still get the same effect. It doesn’t hurt to run air through any of the CSV’s that are 1.25” or smaller. You still get the shot of fresh air each time the pump starts. It just won’t cycle on and off several times while you take a shower, or continuously cycle while a sprinkler is running.

 

[Texas Wellman]

I air mine up twice a year and I "own" several wells, all with galv. tanks. Currently I am getting 20 years out of all my pumps and pressure switches etc and I do not run a CSV either.

 

[Valveman]

Yeah if you maintain it, there is nothing wrong with a galv tank. However, even people who say they will maintain it, always forget. Airing it up twice a year might work for some, but once a month may not be enough for others. It is all in how the water is being used. The more water being used, the more air goes out with the water, and the sooner the tank will become waterlogged. Just one day of running with a waterlogged tank is about like 5 years of wear on the pump.

And yeah if you have a big enough tank, and you make the irrigation and heat pump demands large enough to use exactly the amount of water that your pump will produce, you can get by fine without a CSV.

We could also be just fine with the horse and buggy, instead of switching to automobiles. But horses need a lot more maintenance and are a lot less convenient.

The idea of the CSV with a bladder tank, or a galv tank and an air maker system, is for people to be able to use water anyway they want, without having to maintain anything. As a pump man, I can tell just by the pressure in my shower if everything is OK. Most people can’t tell there is a problem until it is too late. And most people do not want to do anything to their water system but open a faucet when they want water, and shut the faucet when they are finished using water. With a CSV there is really no need to do any maintenance or thinking about how you use your water system. Just like since you now have a car, you no longer need to feed and maintain horses.

It has been my experience that ANY maintenance left for the homeowner doesn’t get done, the pump burns up, and it is all my fault. Which is exactly the truth, because I should have known to make it a maintenance free system that can be used anyway the homeowner wants. And that is exactly what the CSV does.

 

[Masterpumpman]

I'm with you valveman. Those that don't know don't do!

 

[Justwater]

heck even those that do know, don't do. I have an uncle in AC business, he makes a killing replacing units that aren't old just because people don't remember to change their filter.. when they know to.

how many drillers do u see that get 5 yrs out of a rig instead of 15 just because they are too lazy to maintain it properly.

making any type of system with the least maintenance possible is the best way to go, especially for the customer. when u have to go back to a job a year or so later.. even if it isn't ur fault.. u still look bad.

 

[Gary Slusser]

For water treatment with air/oxygen (air injection venturi or with a medical grade oil less air compressor), the best tank is a retention tank or better/best is a 12" x 65" mixing tank that is equivalent to a 120 gal retention tank, that has an automatic float control.

Those type tanks are made for the purpose of maintaining a head of constantly replaced air that the broken up water stream falls down through as you use water. That's where the oxidation comes from, so no head of air, you get little to no oxidation, or filtration. Those type tanks can not rust or add anything to your water unlike galvanized or painted steel pressure tanks, plus they are smaller and lighter and require much less maintenance.