Air in line- submersible well pump

[DYIRich]

System works fine- cut-in/out pressures correct (45 seconds from cut-in to out), draw down OK (about 9 gal. 32 gal. Water Worker tank.
But- considerable air in line pushed into tank at start-up. At cut out, pressure immediately drops about 2lbs. and then holds steady. Some water hammer at start-up.
The water hammer is at check valve just before tank.
Must there be a leak in the line for air to enter, or could a vacuum have the same effect (assuming the check valve at the pump is defective)? Help would be greatly appreciated.

 

[Valveman]

You won't know until you remove the check valve at the tank. There should not be one there anyway. After removing or gutting the check valve at the tank, pressure leaking back can be either a hole in the pipe or a bad check valve. With air in the lines it is usually a hole in the pipe.

 

[Sponsor]

 

[Reach4]

Must there be a leak in the line for air to enter, or could a vacuum have the same effect (assuming the check valve at the pump is defective)?

Vacuum itself will not cause air to be coming out of faucets. However vacuum can cause air to enter, even through spaces too small to leak water.

Vacuum with a check valve can cause a bang as the water turns on.

 

[DYIRich]

You won't know until you remove the check valve at the tank. There should not be one there anyway. After removing or gutting the check valve at the tank, pressure leaking back can be either a hole in the pipe or a bad check valve. With air in the lines it is usually a hole in the pipe.[/QUOTE

Vacuum itself will not cause air to be coming out of faucets. However vacuum can cause air to enter, even through spaces too small to leak water.

Vacuum with a check valve can cause a bang as the water turns on.

OK, lets say the check valve at the tank is holding, but the check valve on the pump is leaking, I see a vacuum could be created in the line which would cause the water hammer. But, if air is entering at a leak between the two check valves it should negate (for wont of a better word) the vacuum, so the air in the line is at atmospheric pressure (not vacuum). Could that (just air) cause the hammer?
If I gut the check valve at the tank, and have a leak, I would know this as the pressure would continue to drop- more than the 2 pounds I'm losing now, right?

 

[Reach4]

OK, lets say the check valve at the tank is holding, but the check valve on the pump is leaking, I see a vacuum could be created in the line which would cause the water hammer. But, if air is entering at a leak between the two check valves it should negate (for wont of a better word) the vacuum, so the air in the line is at atmospheric pressure (not vacuum). Could that (just air) cause the hammer?​

I don't know, but I know you would see significant air coming out of the faucets. You would also see a delay for water to appear as the pipe fills up with water.

If I gut the check valve at the tank, and have a leak, I would know this as the pressure would continue to drop- more than the 2 pounds I'm losing now, right?​

You would know because the pump would cycle to make up for the leakage. Every 2 minutes? Every 24 hours? Don't know. I am rooting for a long period.

The 2 pounds immediately after the pressure switch cuts off? That could be because the pressure switch nipple is not very close to the input of the pressure tank. So the pressure at the pressure switch rises quicker than the pressure at the input of the pressure tank. If not immediate, see https://terrylove.com/forums/index....lbs-of-pressure-at-cut-off.67940/#post-504741 which is what I observed. I suggest that you ignore those two psi, other than out of curiosity.