Pressure tank install questions

I'm going to replace my galvanized tank with a new fiberglass tank.

1) Is there any reason to put a union on the lines going in and out of the tank somewhere?
The current tank doesn't have them, nor has it moved in 30 some years. I can't think of why I'd have to remove it other than replacing it again at some time. If I should use them, is there any reason to use dielectric unions? All of the galvanized piping will be removed and the tank itself isn't conductive.

2) I'm wondering what the fitting is on the copper coming through the wall. It seems like a female adapter but the hex nipple threaded into it seems to have 2 different threads on it. At least the threads look slightly different. One end (further from the wall) looks to have a male NPT thread. The end threaded into the adapter doesn't look the same. Almost like it may be a straight thread. Are my eyes playing tricks on me? Is it really just a female adapter?

Thanks.


Thanks.

That is a flared copper fitting adp. From flare to pipe threads !

The "nut" on the copper is the "union" side of a flare adapter. Which means you DO have a union in the line.

But it looks like perhaps someone soldered the nut to the pipe so maybe its not a union anymore.

I think the steel diaphragm tanks are far better than the fiberglas. You can get a Goulds or Amtrol for 350 to 400 dollars in a 85 gallon size, call the local pump guys. Your galvanized tank will outlast three or four of the plastic ones. The fiberglas tanks are essentially bladder tanks which flex a lot and thus fail sooner.

Why would someone have used a flared fitting rather than just soldering a female adapter on?

So I keep the flared nut and the flared to NPT adapter. Replace everything after that.

Here are some pics of the current setup. Tank is already purchased so it's going in.

For some reason I can't get these pictures to rotate to the correct orientation.......

They may have used the flare because they had the tools to do it, but not to solder it. It might also be the reason they used all galvanized pipe instead of copper.

May as well leave the old tank in too and get some more draw down. Probably will outlast that new one.

ballvalve said:

May as well leave the old tank in too and get some more draw down.

Click to expand...

Not true.

We can't cheat Boyle's law. Generalizing and saying the two tanks are both 16" in diameter, and 51" tall, the new tank will have more drawdown since it's AVC is much lower in the tank. Running the numbers (again generalizing a bit on size so I don't have to spend a bunch of time determining the true volumes), I'll be getting about 4.5 gal more with the new tank (12gal vs. 7.5gal).

The old tank outlasting the new is another question. I don't doubt it would but I'm not going to deal with those crusty old fittings and threads.

What I meant to say is leave the old tank exactly where it is and ADD ON the new one. But your reply tells me you may not understand your system entirely. Your new tank does not have and cannot have an AVC or air volume control, you will get bursts of air in your fixtures because it is a bladder tank which has a precharge and thus cannot be used with an AVC.

Your existing tank has a air RELEASE valve, its the one with the pressure gauge on it. Inside your well you must thave an air maker valve, and on each pump run a burst of air comes in to that tank. Excess is vented out of that air release valve on the center of the old tank. If you do not defeat that air maker valve, your new tank will cause problems.

Its a bit dicy to use a plain tank with a bladder tank, but if you take the OUTLET of the plain tank and plumb it into the the new fiberglas tank, you will get the combination of both drawdowns. The air, which you cannot use with the new tank will be vented from the air release valve on the old tank.

The new tank will give you at least double the draw down of the plain tank because it has a precharge - so size of tanks is not comparable, but why not use them both? You might want to move this over to the well forum and get some more info on what I am discussing.

Before you tear into that nice tank and plumbing, do some deep research on plain tanks and the issues of changing over to bladder or diaphragm tanks. You may not want to pull your pump - but you probably will have to if you do this swap without better information.

The new tank isn't a bladder style. It's a Wellmate SP-9. Intended specifically for replacing galvanized tanks. Looks exactly like a bladder tank though doesn't it.

The old tank does not seem have an encapsulated air chamber, so the amount of drawdown will be determined by the VOLUME of air in it, not the air's pressure. IF it had a "snifter valve" to maintain the amount of air, then its drawdown would be somewhat constant, but as the air is absorbed by the water, its volume, and thus the drawdown diminishes.

Wow - never heard of a fiberglas plain tank. Guess its their bladder tank with the guts removed. Since you have the air release valve or AVC you certainly also have a snifter valve and check valve and bleed off valve somewhere outside the concrete - other wise you would have no drawdown now.

And HJ, even without a seperate air chamber, plain tanks can be pressurized exactly the same as a bladder tank. Of course it must be done with an air compressor and repeated dependending on the particular well. I have a few plain tanks near a plumbed in air compressor and give them a shot of air every few weeks. In that way drawdown goes from about 8 gallons to 15 or more.

I would paint the old tank grey and tee it into the new one

EDIT: just looked at the specs on that tank - quite an interesting bit of technology, so I doubt you could pre-charge it with a compressor. Still stands true with the old one though. I wonder how all that technology on the new tank will hold up over time....

And again, I see two styles, one with a TOP mount air valve that claims increased drawdown, [using some odd looking internal valve] and then a side port that seems to be the same as the galvanized styles.

Give a report after you get it installed.

I'm using the side port tank. I figured a more "regular" AVC would be easier to find in the event that it needs to be replaced. The HT tank series AVC seems to be a little too elaborate for my taste.

http://www.wellmate.com/products_trad.htm#sideport

Have you been able to understand why they claim a larger drawdown in the HT tank? Without a precharge, I do not see the chance for that.

It's not normal and a bit weird...

I'm trying to understand the entire system. Looking for help with that.

There must be a check valve and air admittance valve (maybe that's not the right term) somewhere in the system, correct? Neither is located inside the house so I can only assume they are in the riser pipe.

Is it true to say the check valve must be located between the tank inlet and the air admittance valve? Otherwise the tank wouldn't hold pressure, it would all leak out the air valve.

I found the following on the web. How do I know which setup I have? Looks like there are 2 methods.

If I am outside near the well, I sometimes hear what sounds like water trickling or running for a short period. I'm guessing that's after the pump has just shut off and some of the water is draining out of the riser pipe? That would make me think I have the example on the left with a bleeder orifice and snifter valve.

With the trickle, you have the left hand deal. Never saw the one on the right personally. Some sort of filter material or a gas line filter with a bit of hose to the schrader is a good idea because bugs can get sucked in and spiders close them up. There is a 'micronizer valve' that you can put at the tank and monitor its performance, better than the old hidden set up.

The valve in the well is the bleeder valve or even just a hole in the pipe, and the schrader is your air admittance valve. It may be in the well also.

You have a bleeder & snifter in the drop pipe as shown in the left diagram. I can clearly see in your photo of your pressure tank that is has an air release float valve, similar to what is shown in the right diagram. It is located where the pressure gauge is installed on the tank.

The noise you hear at the well is the water coming out of the bleeder after the pump turns off. If you listen at the tank, you will hear the air coming in for a second each time the pump comes on.