Loud banging noise inside pressure tank & size (gallons)needed for 4 people

[JenL]

Our current water pressure tank makes a loud noise about a minute after a water source is turned off. It is inside the actual tank and not the pipes, etc. Does this indicate a defective bladder?

Second problem: I cannot find any information online about the gallon size tank needed for a family of 4.

 

[Bannerman]

Does this indicate a defective bladder?

It could. When the pump is shut off and the tank drained of water, does air pressure remain on the air side of the bladder/diaphragm when measured with a tire pressure gauge at the Schrader valve on the tank?

The air precharge in the tank is normally set to 2-4 psi lower than the well pump cut in pressure (ie: for 40-60 switch settings, the tank precharge should be 36-38 psi). The precharge is always measured with the pump turned off and while the tank is empty of water and the system pressure is 0 psi. If the precharge pressure is too low, that can result in excess tension on the bladder or diaphragm when the tank is filled, which may lead to tearing of the membrane.

tank needed for a family of 4.

The number of people is irrelevant. The water to be utilized is provided by the well pump.

The tank size required will allow the pump to run a minimum of 60 seconds to refill the tank from when the pump starts to when it shuts off. For instance, if the pump delivers 10 gallons per minute, then the tank will need to hold at least 10 gallons of water. Because approx 3/4 of the tank will contain air, to hold 10 gallons water, an approx 40 gallon tank will be needed.

Short pump cycles are harmful to the pump so it is preferable to obtain a larger tank to provide between 1 - 2 minutes minimum run time.

 

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[JenL]

I will have to figure out how to do what you are saying and get back. The other thing I forgot to mention is, the water pressure in the home is low. I cannot get enough pressure to run a sprinkler properly. This has been going on for about a month. But, the loud sound has been happening for nearly a year.

 

[Reach4]

I will have to figure out how to do what you are saying and get back. The other thing I forgot to mention is, the water pressure in the home is low. I cannot get enough pressure to run a sprinkler properly.

You could probably turn up your water pressure. What pressure do you have now? While watering, what pressure do you have? If you raise the water pressure, you need to adjust the air precharge on your pressure tank.

As an alternative to a helper for taking measurements, you could take a movie of your pressure gauge as you turn various taps on and off. Then review at leasure.

But, the loud sound has been happening for nearly a year.

Show us a photo of the pipe coming from the well, the input to the pressure tank, the pressure gauge, and the pressure switch. I will be looking for a check valve. Your bang occurs when the pump kicks off, right?

Is your pump in down well (submersible)?
Is noticable air coming out with your water?

Second problem: I cannot find any information online about the gallon size tank needed for a family of 4.

I would say 44, or at least 32, gallons. I understand I am being overly simplistic.

 

[JenL]

The psi is 42. No water running. Not sure if tank has any water in it. Did not manually drain it.

 

[Reach4]

The psi is 42. No water running. Not sure if tank has any water in it. Did not manually drain it.

That number will normally be in a 20 psi range, unless you read the pressure right after the pump stops running. That pump turn-off might coincide with your bang.

How big is your current pressure tank? What is the minimum time that your pump runs.

 

[JenL]

Interestingly, around the same time that the tank started making the noise there was noticeable air coming out of faucets, like a burst of air when you would first turn one on. This was in the late summer, when it was hot. After a couple of months it was less and less air. Gradually, as it got colder and colder it never had the air problem. Not sure if heat/cold has anything to do with current problem. The banging sounds used to be a lot louder and frequent, too. We get pretty cold in the winter and somewhat hot in the summer. (slightly southeast of Denver metro)

Yes, it makes the banging sound inside the pressure tank a couple minutes when a water source is turned off; i.e. toilet flush, sink faucet off, outside water valve turned off.

Let me know if you need more photos or close-ups. Thanks! House built in 1974/75. We're owners since 2014.

 

[JenL]

That number will normally be in a 20 psi range, unless you read the pressure right after the pump stops running. That pump turn-off might coincide with your bang.

How big is your current pressure tank? What is the minimum time that your pump runs.

I cannot find any information about the size of the tank. I have called Sears with the serial # and they couldn't find anything about it. She said it must be 20+ years old. It is pretty big, though. I would say it's 4-5' tall and the circumference is more than I can get my arms around.

Have not checked to see how long the pump runs. How can I tell?

 

[Bannerman]

Is the bottom of the pressure tank shown in photo 2432? Can you take a full photo of the tank and of any labels?

If your well pump can't be seen, it will likely be submersible which will be located within the well below the water line. The pump control switch (grey box shown in 2431) which should be located nearby to the pressure tank. If allowing some water to run from a faucet, a click will usually be heard from the pump switch which will indicate when the pumps starts which is when the faucet should be turned off and you begin timing how long before hearing another click to indicate when the pump shuts off.

 

[Reach4]

See attached picture. I am wondering what M is. Maybe an old pressure switch, and A is the one current controlling the pump.

1. Is this in a pit or a basement?
2. Is the pressure tank connected to M or L?
3. Is S connected to F? It looks like it.

I cannot find any information about the size of the tank. I have called Sears with the serial # and they couldn't find anything about it. She said it must be 20+ years old. It is pretty big, though. I would say it's 4-5' tall and the circumference is more than I can get my arms around.

Maybe 24 inch diameter.
Does the label on the tank say anything other than than Sears and the serial number?

I wonder what E and F are. Is one a check valve, I am wondering?

 

[JenL]

I took pressure right after I turned on the outside sprinkler. 35 psi. Waited 2 minutes, while sprinkler still on. 45 psi. Then, after about one minute I turned off the outside faucet. The psi at that point was 53, (more than what the gauge has #'s for.) Waited until the pump turned off (at which point I realized the banging noise is coming from the pump control switch "box" and not from inside the pressure tank.) Took a reading right after it switched off and this was about 53. I can go back down and take a reading since it's been several minutes after pump turning off.

 

[JenL]

In basement

 

[Reach4]

he psi at that point was 53, (more than what the gauge has #'s for.) Waited until the pump turned off (at which point I realized the banging noise is coming from the pump control switch "box" and not from inside the pressure tank.

So the sound is from the box pictured in IMG_2429.JPG ?

Interesting.

You should probably replace the start capacitor in that box. That is not the cause of your banging, but those things age. If that capacitor fails, the pump will not start..

 

[JenL]

All the times before when I would listen for the sound, I was standing by the tank. This time I was standing in between the tank and the well pump switch box (img 2429.) The sound clearly came from the box or at least it looked like that since the box and lines shuddered. I'm sure that's where I detected the loud sound. Right when it switched off. I will turn on water again. And, check.

 

[Bannerman]

Your current tank is listed as 85 gallons.
https://www.searsoutlet.com/br/pdp/craftsman-85-gal-captive-air-tank/41171

It seems a replacement bladder remains available.
Although that tank model is not listed on the Parts Direct page, the verification box indicates it will fit 390.291701
https://www.searspartsdirect.com/product/48uu4aouaa-0042-390/id-u20-14

 

[JenL]

videos. Our birds are very loud and can hear them (upstairs, too, not in basement!) #1 is when you can hear the switch sound of pump turning off. About 30 seconds later is video #2 when you hear the loud banging noise. Doesn't seem to be coming from the box, but the tank. I really thought it was from the box the last time I was down there! Apparently, you can't send videos because the file is too large!

 

[JenL]

Your current tank is listed as 85 gallons.
https://www.searsoutlet.com/br/pdp/craftsman-85-gal-captive-air-tank/41171

It seems a replacement bladder remains available.
Although that tank model is not listed on the Parts Direct page, the verification box indicates it will fit 390.291701
https://www.searspartsdirect.com/product/48uu4aouaa-0042-390/id-u20-14

Thank you for this! I could not find it anywhere. That's a big tank! Way more money than we have to use on a new tank.

 

[JenL]

A well guy came out a year ago when we first had the noises. He said the tank bladder was broken, but the cost between his labor and parts was around $3000. He tested it different ways, but one way was tapping on the side of the tank and indicating water was in the wrong place (or something like that.) The cost is why we didn't do anything and still can't. But, my husband worked in commercial plumbing for several years and said he is able to install a tank or whatever may need to be done.

 

[Bannerman]

You could upload a video to YT or another video site and then post the links to those pages.

If your pressure gauge is somewhat accurate, it appears the pressure switch settings are 32 psi ON and 52 psi OFF.
I would recommend before shutting off the pump and draining the system to check the tank pressure, first depress the 'tire' valve at the top of the tank so see if any water comes out. If water comes out, then there is a hole in the bladder and either the bladder will need to be replaced or the tank replaced.

Since the system pressure is higher than the pressure gauge indicates, the gauge should be replaced with one that indicates a higher pressure range.

 

[Bannerman]

If the tank bladder is broken, then the well pump will be cycling much more than it should which will negatively affect the life of the pump. Unless the pressure tank issue is soon corrected, you may find you may need to replace both the tank and the pump.