Air in water lines.

[RealRobD]

Few days ago there was some sputtering at the faucets, toilet etc.
My first thought was a leaky bladder in the pressure tank.
I drained the system and checked the charge on the tank and it was about 20 lbs.
I knew right away there's my problem. So filled the bladder to 30 lbs and waited.
2 days later I drained the system, checked again and it had lost about 4 lbs.
I replaced the tank and a new check valve yesterday (it was in need anyway as it was very old and rusty) and I'm still getting air in the lines.
My investigation today consisted of making note of the gauge sitting at 50 lbs used no water and came back an hour and a half later and it has not moved.
So I at least know the check valve on the pump in the well is holding.
When the pump comes on, you can hear the gurgling of air (on the pump side, before the tank) for a few seconds and then it flows fine with no air.

I have some ideas of the cause but want to hear from someone else before I express them.

 

[LLigetfa]

The check valve is likely the problem along with a leak in the pipe. Remove the check valve so you can find the leak.

 

[Sponsor]

 

[RealRobD]

The check valve is likely the problem along with a leak in the pipe. Remove the check valve so you can find the leak.

There are two, one just before the pressure tank and one at the pump. Please indicate which one you're referring to. The line is not draining back. If the check valve at the pump was bad, it would. So I'm not sure I follow. And the check valve at the pressure tank is brand new.

 

[FredG]

The one near the tank needs to be removed. Then you will find your leak, which is likely in the down pipe.

 

[Reach4]

Another possibility is air introduced during softener regeneration, but for sure your pressure tank was a problem.

I replaced the tank and a new check valve yesterday (it was in need anyway as it was very old and rusty) and I'm still getting air in the lines.

Confirm that the check valve that you changed was down the well by the pump. If your only check valve is at the pump, then there is still another way for air to come in... you used a lot of water, such as might happen when your backwashing iron filter regens, and the water level in the well fell to the intake ports on the pump.

If you have an above-ground check valve, you normally don't want one of those with a submersible pump, as FredG was getting at.

 

[RealRobD]

Another possibility is air introduced during softener regeneration, but for sure your pressure tank was a problem.


Confirm that the check valve that you changed was down the well by the pump. If your only check valve is at the pump, then there is still another way for air to come in... you used a lot of water, such as might happen when your backwashing iron filter regens, and the water level in the well fell to the intake ports on the pump.

If you have an above-ground check valve, you normally don't want one of those with a submersible pump, as FredG was getting at.

Removed the replacement check valve at the pressure tank. Turned the pump on and recorded the pressure. Will check back in an hour to see if it has dropped. So it's obvious now that the pump has a built in check valve. What was the purpose of the check valve at the tank? The system has been working flawlessly for 40 year by the way.


EDIT: It is slowly dropping.
Would it be better to put the check valve back in to keep the tank full and just deal with the sputter or just leave it as is? It may take a few days to get someone out to lift the pump. My thought is that the pump will run less if the pressure is kept.

 

[Reach4]

What was the purpose of the check valve at the tank? The system has been working flawlessly for 40 year by the way.

Couple of reasons. It think there is still a at least one state that requires an above-ground check valve. I think that is misguided.

I am thinking that having an above ground check valve was important in drain back and with the ability to insert air for a "conventional"/galvanized tank. Those check valves had a port for a weak-spring Schrader valve called a snifter valve. Those would admit air on purpose. Then the tank would have a valve to release excess air. So I am speculating that had some influence.

A very strong advantage to no above-the-water check valve is that the line stays pressurized, even in the face of a tiny leak. If there is a small leak, the pump would cycle, and restore any lost pressure before a vacuum could develop.

Sometimes it is easier to remove the poppet of the check valve, and keep the housing in place, without otherwise changing the plumbing.

It does work around a leaky check valve at the pump, but can cause a water bang when the pump starts. But a check valve at/in the pump that leaked slightly with a topside check valve can seal better with the pressure helping to hold its poppet closed.

 

[RealRobD]

Couple of reasons. It think there is still a at least one state that requires an above-ground check valve. I think that is misguided.

I am thinking that having an above ground check valve was important in drain back and with the ability to insert air for a "conventional"/galvanized tank. Those check valves had a port for a weak-spring Schrader valve called a snifter valve. Those would admit air on purpose. Then the tank would have a valve to release excess air. So I am speculating that had some influence.

A very strong advantage to no above-the-water check valve is that the line stays pressurized, even in the face of a tiny leak. If there is a small leak, the pump would cycle, and restore any lost pressure before a vacuum could develop.

Sometimes it is easier to remove the poppet of the check valve, and keep the housing in place, without otherwise changing the plumbing.

It does work around a leaky check valve at the pump, but can cause a water bang when the pump starts. But a check valve at/in the pump that leaked slightly with a topside check valve can seal better with the pressure helping to hold its poppet closed.

Thank you for the insight.
Since the leak back is significantly slow, I'll not worry about it and leave the valve out. And keep it out once the repair is made.
Are there any submersible pumps that have built in check valves or are they always incorporated in-line just above the pump?

EDIT: I just wanted to add that the faucet pressure is significantly low now that there is no check valve by the tank.

 

[Reach4]

Are there any submersible pumps that have built in check valves or are they always incorporated in-line just above the pump?

Most do. However it is OK to have a check valve in the pump, and another right above the pump. There are some cheap Chinese ones that do not.

EDIT: I just wanted to add that the faucet pressure is significantly low now that there is no check valve by the tank.

That is odd.

What is the pressure at the pressure gauge?

You usually want the air precharge pressure in the pressure tank to be 2 psi below the cut-in pressure. The precharge is measured and set with the water pressure zero.

You may have a cartridge filter that became clogged. You may have a faucet spout aerator that needs cleaning. So if the tub flows well, but your lavatory or kitchen faucet does not, consider the aerator.

 

[RealRobD]

Most do. However it is OK to have a check valve in the pump, and another right above the pump. There are some cheap Chinese ones that do not.


That is odd.

What is the pressure at the pressure gauge?

You usually want the air precharge pressure in the pressure tank to be 2 psi below the cut-in pressure. The precharge is measured and set with the water pressure zero.

You may have a cartridge filter that became clogged. You may have a faucet spout aerator that needs cleaning. So if the tub flows well, but your lavatory or kitchen faucet does not, consider the aerator.

Sometimes I'm probably a danger to myself and others.... I forgot to turn the outlet valve back on.
The older you get, the more things like this you do

 

[FredG]

Grundfos and Goulds pumps have stainless check valves that rarely fail. The rest use cheap plastic. That may be another reason why multiple check valves are used.