# air pressure in well pump pressure tank? One more time please.

• posted on December 9, 2004, 3:38 am
I know this subject has come up often, so often with different variables that it is difficult for me to google the answer I'm looking for.
In my new (new to me) home, the pump was short cycling (it ran after about 1 quart of water was used, and who knows how many off and on cycles during a shower?)
If I am correct, the air pressure in the tank should be about 2-3 pounds less than the cut in pressure? OK so far?
Now, when and under what conditions do you measure and adjust the pressure in the tank? With the power to the pump turned off and the water runs until it empties the tank...*leaving the water valve open*.
Or is that where someone said you could damage the bladder? Don't they come pre charged? Wouldn't they self destruct before installation if that was the case? I must have read something wrong there?
I don't see how it could be set with any restriction on the water side of the tank, since if the water side is closed, the two sides will always be equal pressure.
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Thanks,
Tony

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• posted on December 9, 2004, 3:50 am

Set it to 2 PSI lower then your cut in pressure with the pump off and tank empty of water.
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• posted on December 10, 2004, 3:42 am
PAUL100 wrote:

Thanks.
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Tony

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• posted on December 11, 2004, 3:39 pm
No, you won't 'blow the bladder'. It will usually collapse and cover the the tank outlet giving a 0 psi reading when you shut the pump off and drain the tank. The water enters into the bladder, not air. You (and the others)_ are correct. 2psi below cutin. You can shut off the tank inlet/outlet valve while pressurizeing so you aren't trying to pressurize the entire house system. Not necessary but a bit faster. Harry K