I have an Aqua Air V140 tank. It pump runs often while running water. Once I turn the water on it doesn't take long before the well pump turns on. Once it starts running it doesn't tale long for it to turn off again.

Tell us how long "it doesn't take long" is.

Could be heading towards a waterlogged tank. HK asked a good question.

As best as I can figure on the web, the V140 is a 45 gallon tank. You should be able to run water for at least a couple of minutes, and likely more, before the pump cuts on. If you are talking about 10 or 15 seconds to come on and also to shut off, then you likely have a tank problem.

You might want to be sure the tank pressure is set correctly. With the power off and the tank drained down to zero pressure, the tank pressure should be set to 2# below the cut in pressure. So if the pump is set to come on at 30#, for example, you would set your tank pressure to 28#.

Tell us how long "it doesn't take long" is.

15 - 20 seconds

There are, it seems to me, two possibilties:

1. It's possible, but not likely, that the switch is defective. There should be about a 20# pressure interval between the pump cutting on (at low pressure) and cutting off (at the high point). You need to check that. Just let water run and watch the pressure gauge. It should swing SLOWLY down to the point where the pump cuts on, and then SLOWLY up to the point where the pump cuts off. Should be around a 20# difference.

2. Tank going bad. There is a flexible "bladder" in your tank to separate the water from the air cushion which has to be at the top of the tank. If that bladder ruptures, then the air cushion, over time, will gradually be absorbed into the water and go away. That is likely your case. If it is, then the situation will gradually get worse until the pump's cycle will be just a few seconds instead of 20 seconds. Only permanent solution is to replace the tank. Thankfully, that is not a tough job.

For the short term, you can drain the tank and put air into the valve at the top. Set the pressure at 2# below the pressure point where the pump cuts on. When you turn the pump back on, your cycles should be much longer than 20 seconds. But as time goes by, it will return to it's current sad state.

There are, it seems to me, two possibilties:

1. It's possible, but not likely, that the switch is defective. There should be about a 20# pressure interval between the pump cutting on (at low pressure) and cutting off (at the high point). You need to check that. Just let water run and watch the pressure gauge. It should swing SLOWLY down to the point where the pump cuts on, and then SLOWLY up to the point where the pump cuts off. Should be around a 20# difference.

2. Tank going bad. There is a flexible "bladder" in your tank to separate the water from the air cushion which has to be at the top of the tank. If that bladder ruptures, then the air cushion, over time, will gradually be absorbed into the water and go away. That is likely your case. If it is, then the situation will gradually get worse until the pump's cycle will be just a few seconds instead of 20 seconds. Only permanent solution is to replace the tank. Thankfully, that is not a tough job.

For the short term, you can drain the tank and put air into the valve at the top. Set the pressure at 2# below the pressure point where the pump cuts on. When you turn the pump back on, your cycles should be much longer than 20 seconds. But as time goes by, it will return to it's current sad state.

OK... With one faucet running, the pump kicks on at 38# and runs for 7.6 seconds when it reaches about 72#. 32.6 seconds later it is down to 38# and starts running again.

Tank must be bad. You can try doing the last paragraph above (For the short term, you can drain the tank and put air into the valve at the top. Set the pressure at 2# below the pressure point where the pump cuts on. When you turn the pump back on, your cycles should be much longer than 20 seconds. But as time goes by, it will return to it's current sad state.). If that works, then you know it is the tank.

You can also push the valve stem in the air valve at the top of the tank for a few seconds. If water comes out, then you have your answer.

OR you can use a screw driver handle to tap tap tap up the side of the tank. You can tell when you have gone from water to air by the difference in sound produced by the tap. The water should be around halfway up the tank. In your case, it is probably much nearer the top.

I agree with John, that sounds like a ruptured bladder.
To confirm, press the needle in the schrader valve and let all the air out. If after letting the air you get water, the bladder is ruptured.

Then turn pump off. Open the drain valve. With drain valve open, pressurize the tank to 36 lbs. Close drain valve and turn pump on.

That should make your tank operate properly for a short period until you can replace it.

I agree with John, that sounds like a ruptured bladder.
To confirm, press the needle in the schrader valve and let all the air out. If after letting the air you get water, the bladder is ruptured.

Then turn pump off. Open the drain valve. With drain valve open, pressurize the tank to 36 lbs. Close drain valve and turn pump on.

That should make your tank operate properly for a short period until you can replace it.

Thank you everyone for all your help!!