Is it normal for the well pressure tank to lose its air pocket?

[strantor]

I grew up on well water but we never had the problems I've been experiencing for the past 7 years in this house, because my childhood home had a bladder tank.

This house has just a 120gal tank with no bladder. Water enters the bottom, water leaves the bottom; air gets trapped in the top, with theoretically nowhere to go, providing a "cushion" of air for the pump to push against.

What happens is, that pocket of trapped air somehow slowly disappears. The water level gets higher and higher, and the well pump cycle gets shorter and shorter until its running 5 seconds on / 5 seconds off during a shower.

I remedy it by periodically (when it gets bad, maybe every 6-9 months) turning the well pump off, open a drain, connect my air compressor to the tank, and let the compressor run until it pushes all that water out, then turn the well pump back on. The result is a dramatically longer (better) pump cycle time.

I understand the problem and the solution, I just can't figure out the cause. Is this something everyone without a bladder tank experiences? Or is there something wrong that I could fix to prevent this?

I am sure that air is not leaking out from anywhere at the top of the tank.

 

[Oaktree]

I didn't even know they made non-bladder tanks anymore. Yeah, the type tank you have is prone to that. I think over time the air gets absorbed into the water.

 

[ruffdog]

Yep, we had a non-bladder pressure tank at the farm. If it cycles too often it was time to pump some air into it. Even with a bladder type, I empty the water pressure (do it while watering the yard) and check the tank pressure. Most times I have to pump some air in. Having the right amount of air just makes the system work right.

 

[strantor]

Yep, we had a non-bladder pressure tank at the farm. If it cycles too often it was time to pump some air into it. Even with a bladder type, I empty the water pressure (do it while watering the yard) and check the tank pressure. Most times I have to pump some air in. Having the right amount of air just makes the system work right.

Oh, I didn't know that. I remember my dad's bladder tanks had valve stems on them like you could pump them up with a compressor, but I never had to touch them. I doubt my dad did either; that seems like something he would have told me to do. Our well was at least 50 yards from the house so maybe we just never noticed the pump short cycling.

 

[ponytug]

There is often a Venturi, aka, an inductor, inline to suck in a little air to make up for the air that is being absorbed by the water. It may need cleaning.

As it gets colder, water can absorb more dissolved gasses.

All the best, Peter

 

[EarPlug]

Standard bladderless water pressure tanks are normally used for drain back systems. These are systems where the water drains the line back to the well to prevent freezing, after every pumping cycle. These standard pressure tanks use a air volume control in the side of the tank, up about half way. The water line, when it drains back, will have air in the water line. The air volume control allows the air in the line to escape from the tank until the water level rises to the point that it pushes the control float closed. Once the float closes off the air escape hole, the pump pressurizes the water pressure tank to shut off the pump. A 2 hole check valve is used to allow air to come in through a snifter valve, which looks like the air valve on your tire, to allow the water to drain back to the well, where a drain back valve allows the water to drain back into the well.

 

[ruffdog]

Standard bladderless water pressure tanks are normally used for drain back systems. These are systems where the water drains the line back to the well to prevent freezing, after every pumping cycle. These standard pressure tanks use a air volume control in the side of the tank, up about half way. The water line, when it drains back, will have air in the water line. The air volume control allows the air in the line to escape from the tank until the water level rises to the point that it pushes the control float closed. Once the float closes off the air escape hole, the pump pressurizes the water pressure tank to shut off the pump. A 2 hole check valve is used to allow air to come in through a snifter valve, which looks like the air valve on your tire, to allow the water to drain back to the well, where a drain back valve allows the water to drain back into the well.

Our bladderless system did not drain back to the well or have the other stuff you list. I'm thinking we didn't need it as the tank etc was in a pit and wouldn't freeze.

 

[pmsmechanic]

I have the same setup and yes twice a year or so we need to add air to the tank. I changed the plumbing around so that the water just goes into the tank. Not through the tank. I installed a "T" in the inlet side before the tank so that the water continues out the "T" to the house.That seems to lessen the turbulence inside the tank and I noticed that I don't have to fill air as often.

 

[strantor]

Standard bladderless water pressure tanks are normally used for drain back systems. These are systems where the water drains the line back to the well to prevent freezing, after every pumping cycle. These standard pressure tanks use a air volume control in the side of the tank, up about half way. The water line, when it drains back, will have air in the water line. The air volume control allows the air in the line to escape from the tank until the water level rises to the point that it pushes the control float closed. Once the float closes off the air escape hole, the pump pressurizes the water pressure tank to shut off the pump. A 2 hole check valve is used to allow air to come in through a snifter valve, which looks like the air valve on your tire, to allow the water to drain back to the well, where a drain back valve allows the water to drain back into the well.

That doesn't sound like my system. There is no control float, nothing inside the tank (I've seen inside it). There's a pump underground and a check valve, then the tank, then a water softener, and straight into the house. The only control that I know of is a pressure switch.

 

[Hoot Owl]

When I did Plumbing, Heat and Electric. We had a list of people with bladder less tanks. After the first of the year we would go around and put air in them. Some of the larger farms we did it twice a year. The water would absorb the air over time.