Bladder tank increasing pressure.

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Old 04-13-11, 05:36 PM
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Bladder tank increasing pressure.

I have a 4" submersible 3/4 hp Flotec pump 220 v about 90 feet down. My bladder tank in 20 gallons. I have my pressure switch set for ~35-60 psi. About a month ago I noticed that when the tank was empty the air pressure was about 60 psi so I bled off some air to closer to 30 psi. Now the pressure on an empty tank is back up to 60 psi. Without adding air what would cause the pressure in the tank to rise? Is it a defective bladder tank? I would probably replace it with a 36 gal tank if it is the problem.
 
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Old 04-13-11, 06:12 PM
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Its impossible.

I would say your gauge is off or the tank is not drained properly. Pressure gauge or tire gauge off?

If you had 60 psi in the tank then the bladder would collapse and you would have no water until the pump built up the pressure again. At 60 psi air and a 35/60 switch the bladder would collapse asap when you turn the water on. You would go from a 60 to 0 psi in seconds.

Turn the pump off and open a faucet to relieve all pressure. Then test with the air gauge.

Mike NJ
 
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Old 04-13-11, 06:17 PM
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A pressure tank is suppost to be from 2 to 5 psi lower then the maximim setting of the pressure setting on the pressure switch. Not 30 psi lower.
 
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Old 04-13-11, 06:31 PM
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A pressure tank is suppost to be from 2 to 5 psi lower then the maximim setting of the pressure setting on the pressure switch. Not 30 psi lower.
That is incorrect.

The pressure tank should be set about 5 psi lower then the cut in pressure. So if he cuts in at 35 psi then the tank should be about 30 psi. This gives a buffer for pump lag. If the psi in the tank was set to say 40 psi the bladder would collapse at 40 psi but the pump will not kick on until 35 psi, and there would be a no water situation. The psi would go to 0 when this happens and you will need to wait until the pump kicks on and builds the pressure back.

Mike NJ
 
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Old 04-13-11, 08:16 PM
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The pressure in the bladder should be 2 to 3 psi less than the cut-on pressure of the pressure switch.
With the power off, drain the tank of water.
Check the psi on the bladder. If your switch is on at 35psi there should be 32 to 33 psi on the bladder.

When the bladder shows 60 psi, are you checking it on the top of the tank where the bladder valve stem is? And is that with or with out water in it?
If water comes out the valve-stem on top of the tank, its time to change the tank.
That means the bladder is bad.


lawrosa;


If you had 60 psi in the tank then the bladder would collapse and you would have no water until the pump built up the pressure again. At 60 psi air and a 35/60 switch the bladder would collapse asap when you turn the water on. You would go from a 60 to 0 psi in seconds.

What do you mean by collapse?
If it is a working bladder it can not collapse no matter the pressure.
 
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Old 04-13-11, 10:39 PM
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What do you mean by collapse?
If it is a working bladder it can not collapse no matter the pressure.
If there is more air in the tank then the cut in pressure the air will force the bladder down and block the water flow out of the bladder. (collapse)

The water is in the bladder. The air is in the tank.

Anyone on a well? Example: With a 40/60 put 50 psi in your tank and let me know what happens.

Mike NJ
 
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Old 04-14-11, 04:45 PM
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Originally Posted by lawrosa View Post
If there is more air in the tank then the cut in pressure the air will force the bladder down and block the water flow out of the bladder. (collapse)

The water is in the bladder. The air is in the tank.

Mike NJ

On a bladder tank, the water is on the outside of the bladder.
The bladder is hung from the top, that is why the valve stem is on the top of the tank.
If water is in the bladder, the bladder is bad and the tank would need to be replaced.
 
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Old 04-14-11, 06:56 PM
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On a bladder tank, the water is on the outside of the bladder. The bladder is hung from the top, that is why the valve stem is on the top of the tank. If water is in the bladder, the bladder is bad and the tank would need to be replaced.
You just kidding me right??






Mike NJ
 
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Old 04-14-11, 07:41 PM
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Look at the picture again.
The water is on the outside. The air is on top.
The water is free to flow in and out. If water fills the top or the "bladder" that means there is a hole in the bladder, and at that point the water can not get out, and you would be correct.
The air is the only thing that is captive, the water is not, there for, the air is in a bladder.
That is why they are called captive air tanks.

The tank in the pictures are a diaphragm type. It attachés to the sides.
A bladder tank has a bag of sort on the inside, and is only attached to the top of the tank.
 
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Old 04-14-11, 08:54 PM
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I apologize for any mis communication. We are talking apples and oranges.


The tank in the pictures are a diaphragm type. It attach�s to the sides.
A bladder tank has a bag of sort on the inside, and is only attached to the top of the tank.
In the picture it says bladder on the top left. it could be called a diaphram too.

Look at the blue tank. Do you see where the air is added? It is added in the steel portion of the tank. This air keeps pressure on the bladder where the water is held. The water is in the bladder and never touches the steel of the tank.

You did make this statement.

On a bladder tank, the water is on the outside of the bladder.
You made this statement also.

The bladder is hung from the top, that is why the valve stem is on the top of the tank.
Again look at the blue tank in the pic.


But all in all you are correct if you are talking about those fiberglass products such as well mate. I personally think they are inferior and would never use one. Yes it does have a captive air bladder. I think regardless how they are made all tanks are called captive air. Kind of like band aid is really a adhesive bandage. Ya know what I mean?

Captive air type tank you descibe.

http://www.wellmate.com/Files/Knowle...structions.pdf

So with that my examples are of tanks I use here in NJ. The water never touches the steel.

You are correct if using a fiberglass type tank.


Whew!!!!!!!


Anyway I dont want to get off topic. Hopefully the OP will chime in so we can help him out.

Mike NJ
 
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Old 04-14-11, 09:37 PM
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Originally Posted by lawrosa View Post
We are talking apples and oranges.


Anyway I dont want to get off topic. Hopefully the OP will chime in so we can help him out.

Mike NJ

I went back and read all the post.
I can see what your saying, and I fully agree with you on the fiberglass tanks.
I would never install one myself. However I have replaced more than few with the steel ones.
Fiberglass just cant take the sun.

Well, one thing about this thread is, if the op or anyone else that reads this, they will get a lot of info on bladder/diaphragm tanks...
 
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Old 04-15-11, 11:58 AM
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Lots of Information...thanks.

I'm sorry for not reading your relpies before today. Well I probably sent this discussion off on a tangent by calling my tank a "bladder tank" instead of a "diaphram tank". It's a Well X-trol and looks exactly like the one in the picture. I am sure my gauge is accurate enough and I am measuring the pressure with the tank empty. The higher pressure in the tank was causing a momentary no-water situation before the pump started and pressure recovered. When I bled off 30 psi it functions normally. So my original question is: What would cause the air pressure above the rubber diaphram to increase without adding any compressed air?

***I just measured the air pressure in my tank with the water empty and it is at 40psi.
 

Last edited by BobBad; 04-15-11 at 12:12 PM. Reason: Added information
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Old 04-15-11, 12:20 PM
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What would cause the air pressure above the rubber diaphram to increase without adding any compressed air?
It is impossible.... I know of no physical way that could happen.

Mike NJ
 
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Old 04-16-11, 11:56 AM
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hi bob –

I AM NOT AN EXPERT like the guys helping you here on the forum. But I am on a well with a submersible pump, 40-60 switch, and a diaphragm tank. Are you sure your pressure gauge is OK? (I don’t mean your tire gauge). I mean the pressure gauge mounted on your system near the tank.

I had a pressure gauge that would never read lower than 40. I would drain the tank and it would read 40. But it would read correctly (or at least it looked OK) between the 40-60 range when the system was operating.

I figured maybe it had something to with the gauge operating just between the 2 points (40,60) over the years, and thus maybe mechanically something gets gummed up and so someday the gauge is just incapable of dropping below the range it has operated in over the years. Just a guess…maybe nonsense.

But if your pressure gauge would in fact stick up at the cut-off point (60), but only sometimes, could that be causing confusion? I realize that you say your tank is empty when you check so I assume you mean that you did in fact drain all the water from the tank with the boiler drain valve. And I think you mean you are checking the pressure with a tire gauge at the top of the tank when the tanks is drained and when no more water is coming out of the boiler drain valve. And you are not reading the pressure gauge on the system with the tank empty to determine the pressure (but it should be zero)– but instead you are using a tire gauge on the tank to measure the pressure.

Not trying to insult you Bob, just thinking of all the things I did wrong learning the little bit I know. So I figured others could make some basic mistakes also – no matter how competent they are.

Wow, you really have a mystery there! If you find out what the problem is you got to post back, I don’t know about the other guys but the mystery is killing me(LOL)!

Good luck!
 
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Old 04-16-11, 09:23 PM
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bob,

i'd like to know if when you turn off power and completely drain the system (leaving the drain faucet open)... if schrader valve on tank reads 60 when you previously took these same steps and set it to ~30, is the tank completely empty when you shake it a little? i'd also like to know if you left the power off with tank drained and valve still opened for several minutes.. does that reading go down any? its not unheardof, you could be getting water on the wrong side of the diaphragm due to a small hole.

and yes, all that happens when there is more air in the tank than switches cuton setting is that there is a pause in the water before pump kicks on. i get calls on that all the time.
 
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Old 04-18-11, 07:27 AM
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I have been monitoring my well system for some time now. I noticed a month ago that the pump was not shutting off i.e. reaching the cut-off pressure. I thought my pressure switch was going bad. I re-adjusted the switch. Then I was getting the momentary "no-water" condition before pump cut-in. When I checked the air pressure at the top valve stem I found that the air pressure had increased to 60psi. I then bled off some of the air pressure and the system returned to somewhat normal. Had I misread that air pressure and bled off 25psi or more then my air pressure now would be very low. But it is now around 40psi.
Also I pulled my well pump last week and tested the flow. I was getting about 10gpm. I found thick iron deposits on the pump inlet screen and cleaned it off.
 
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Old 04-18-11, 08:14 AM
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I read you have a 35-60psi pressure switch. As far as it not kicking off, the tube that goes to the switch may need to be cleaned. Fittings also. They get iron deposits in them and affect the function of the switch.

Also the tank cant make air. Just say the bladder broke and your well pump was cavitation and making air pressure it would show itself as air in the lines when you use water, and the pump coming on and off in rapid sucession.

I feel you may have read the pressure at the tank with out it drained or your well gauge and or tire gauge is faulty.

If your well pump kicks on at 35psi I would raise it to 40psi and set the tank pressure to 35psi. Do this when the power to the tank is off. Turn off a valve after the tank and drain all the water from the tank with the hose bib at the bottom. You should have no more water coming out and the well gauge should read zero.

Then check and adjust the pressure in the tank.

Hope we are helping you here. Your doing great.

Mike NJ
 
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Old 04-19-11, 06:56 AM
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This happens all the time with diaphragm tanks. The diaphragm has a hole in it. The water gets on top of the diaphragm, increasing the pressure in the air chamber. Then the water can’t get out of the air chamber, because the diaphragm seals over the water inlet hole. You need a new tank. But if you install a new tank without solving the problem that caused the bad diaphragm, you will be forced to repeat the process again. “Those who don’t learn from their mistakes are doomed to repeat them.” Cycling on and off bends the diaphragm back and forth like bending a wire until it breaks. Stop the cycling and you will solve this problem and many others. A larger tank will only reduce, not eliminate the cycling.
 
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Old 04-19-11, 07:22 AM
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Hey valveguy, I have never seen more pressure appear like that.

The water gets on top of the diaphragm, increasing the pressure in the air chamber.
He said he is checking the pressure empty. Also if he had a hole would'nt the pump cycle alot? He does not state this. He would get air in his water initially until it leaked out of the tank and became water logged. Also I think he would get water out of the schrader valve, which he did not say he did. Water cant be compressed but air can and will compress the same at 60 psi at the well pump cut off.



I am more prone to think he added too much air on a not to accurate air pump, and/or, did not drain the tank fully.

Mike NJ
 
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Old 04-19-11, 07:59 AM
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The more water that gets on top of the diaphragm, the less draw down the tank can deliver. So yes the pump should be cycling more often. Many people think it is normal for the pump to be clicking on and off, and they don’t notice if it is doing so every 30 seconds compared to every 60 seconds, which is a bad thing. But if you keep letting the excess air out of the air chamber, it will eventually fill with water, and be completely waterlogged. Then it will click on and off as fast as you can say “click on and off”. Water will come out of the Schrader valve now, if you let all the air out first. But you may have to turn on the pump to force water out of the Schrader valve. The air chamber has to be completely filled with water, before water will actually come out of the Schrader. If there is no pressure in the water side of the diaphragm, there is nothing to push water out of the Schrader.
 
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Old 04-19-11, 08:10 AM
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Then it will click on and off as fast as you can say “click on and off”.
Thats funny. You made me laugh...LOL

Yeah, you need to know how thing run normal before they start acting up, so you know whats normal or not. Then you start attuning to things.

Everytime my wife hears the well pump come on she thinks there a leak and a flood somewhere. To find after yelling upstairs that the kids flushed to toilet, or used the sink up stairs...lol.

Mike NJ
 
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Old 04-19-11, 02:11 PM
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I will continue to monitor the system. I have not experienced any short-cycling or water released thru the Schrader valve.
Thanks for all of your help and information. I'm leaning towards replacing the tank anyway. It is 24 years old.

Bob
 
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Old 06-04-11, 06:49 PM
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Red face Update on Bladder Tank increasing pressure

During the past two weeks I've replaced my submersible pump and my diaphragm tank. My pump was unable to reach the cut out pressure and kept running. I adjusted the pressure switch down but it got worse. I replaced the pressure switch and found that the 1/4 in inlet pipe was clogged with iron deposits. I'm guessing that the high iron content also wore out the plastic impellers on the Flotec pump. The new pump has plenty of pressure and volume but was cycling too often. Yesterday I put in the new 32 gal Wel-X-Trol tank and all is working great. The old tank was still full of water when I cut it off. I had to drill holes into the side to drain it and carry it out to the trash! Obviously it developed a hole in the diaphram allowing water above it and trapping it there. Thanks again to all of you, especially Valveguy, who correctly explained the water pressure on top of the diaphragm increasing the readings. Now I have to get my Culligan softener cleaned out and working properly again. I took it apart and found it caked with iron deposits. I'll be visiting the water softener forum!
 
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Old 07-25-11, 11:20 AM
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Thanks Bobbad and Valveguy. I had the exact problem with my tank increasing air pressure. Even the people at the tank manufacturer didn't understant the problem. The OEM and Lowes warrantied the tank after I was able to explain the tank problem!!! Thanks! Solved a huge headache for me!
 
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Old 07-30-11, 07:24 AM
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After the pump shuts off the pressure is the same everywhere in the plumbing system, unless the pressure tank is preloaded to a higher pressure in which case a gauge at the top of the pressure tank will read that higher pressure.

You are seing the pressure rise to 60 psi because the pump did not shut off until the pressure got to 60 psi. Adjust the start and stop pressure switches as desired.

(Or maybe your gauge is inaccurate)

It doesn't make any difference whether the bladder holds the water or holds the air. The problem with a hole in the bladder is that you can't easily get all of the water out of the tank in order to recalibrate (repressurize) the tank properly.

Preloading the tank with too much pressure can cause the bladder to herniate out of the bottom opening, possibly making a hole in the bladder.

If you don't have recalibrating instructions, turn off the pump, open a faucet, and slowly pressurize the tank to about 5 psi. This will take some time as the water is forced out of the pressure tank and out of the faucet. Then close the faucet and turn the pump back on. THe pressure will now rise to the cutoff pressure.
 

Last edited by AllanJ; 07-30-11 at 07:49 AM.
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