water logged tank?

we have a shallow well jet pump water system in an area with a high water table. The system has worked great for over 35 years.
The pump and the small pressure tank are in a pit 6ft befow surface. The pressure tank is not a pre pressurized tank.
It did become water logged about 3 months ago (which was rare). We drained it, re-primed it and it worked fine, for 3 months
Now it is acting like its water logged again but this time it cycles so much that the water flow at the faucets actually pulsates.
Questions: is it possible for it to become that badly waterlogged? and this quickly? or coud there be something else going on with it? if so, any ideas? and any solutions?
FYI this year, we did have an abnormally about of rain.

thanks

 

So to confirm, you have a captive air tank and not a bladder tank?

I have never had a captive air tank and assumed they were very old technology which if it's 35 years old would tend to support!

I dont see how rain would have any effect on a tanks operation regardless of type!

 

I haven't had a well since 1991 but I mine was also a non bladder tank. Seems like mine would become water logged about once a year. The air has to be going somewhere - check for leaks, especially at the tank.

 

I had that style of tank at my old shop and store. It was quite old. Mine started requiring frequent drain downs too. It turned out the tank was getting tiny pinholes in it. It would allow the air to leak out and just a drop of water and then it would seal.

 

Maybe I don't understand a "non-bladder" tank well enough but wasn't the bladder designed to keep the air and the water separate, since if it is not, the air will dissolve into the water over-time. I would think that is where the air is going and yes, that tank should require the addition of more air, on frequent intervals, for it to work properly.

 

A non-pressurized pressure tank is equal to an insufficiently prepressurized pressure tank.

When the pump is turned back on, water will enter a non-pressurized pressure tank until the air inside is squeezed enough so its pressure equals the pressure of the water imposed by the pump. At that moment most of the inside of the pressure tank will be filled with water which is equal to a pressure tank coming close to the waterlogged condition. Only a small amount of water usage will let the air in the pressure tank expand and drop to a low enough pressure to start the pump.

Nonbladder tanks need to be prepressurized to the same 2 PSI below pump turn on pressure. They have yet another disadvantage in that if so many faucets are used to overdraw the pump then the prepressurizng air is let out the faucets and another prepressurization (you could say calibration) needs to be done.

 

These non bladder tanks are typically older and do require more maintenance. They are galvanized tanks. Typically the pump was shut off and the tank drained. When the pump was restarted a pocket of air was caught at the top. This pocket could stay there quite a while or dwindle quickly. I eventually added a Schrader valve to the top of the tank and would air when needed.

 

That's about how I understood them as well, but I would think that unless it had some automatic way of replenishing its trapped air supply, then how it is operating now (works for a few months then short cycles) would be how it would always have worked.

If this guy says this problem is something new then I wonder why that is.

 

Some non-bladder tanks have an automatic air replenishing system (sold separately) that is activated by the pump cycling. This system has two parts, part 1 adds air. It is inaccurate and errs on the high side so part 2 lets out the excess air periodically with a hissing noise to keep said excess air from coming out of faucets.

If the system had become depressurized, this replenishing system could take a few dozen pump cycles to automatically get the proper pressures and proper time between pump restarts.

 

My very old bladder tank developed a pinhole leak so small I couldn’t see the spray, but I felt it. Maybe do as marksr suggested and look the tank over very carefully. Seems to me a very small and new leak might be the problem. Just a thought.