What would cause air to be pushed into pipes from a well tank?

Question

The faucets have been hissing of air for the passed few months, and it has been getting progressively worse. It is usually worse in the morning when we get up and in the evening when we get home.

We have a Well Mate VM series tank. At first I thought maybe the bladder failed and the air was coming from the other side of the bladder. So I knocked on the tank and it sounds hollow on top to me.

Then I thought the air bubbles were coalescing at nearby high point during lack of use.

Then the other day I was near the tank when I heard the air leave the tank and travel through the pipes.

Any ideas what may be causing this?

Answer 1

It's possible it's the pressure tank. To check the pre-charge, turn the pump off, and then open a faucet to let all the water out. Check the pressure in the tank using a tire pressure gauge (there is a valve on the top). This should be 2-10 PSI below the "start" pressure of the pump: eg, if your pump comes on at 40psi (on at 40/off at 60 is the most common setup), the pressure tank pre-charge should be 30 to 38psi. If it's lower, fill it (and keep your faucet open). If the bladder is broken, you won't be able to fill it and there will be air coming out of the open faucet.

It's also possible something is wrong with the check valve and air is getting in the line from the well to the house. To check this, turn the water off to your house (usually there is a valve somewhere after the pressure tank) -- it's essential to isolate the pressure tank from the rest of your house to do this test. Run the pump until the pressure tank is full and it turns off, and then watch the pressure gauge. If it's slowly going down, you are losing water somewhere either due to a break in the pipe, or a broken check valve.

Answer 2

Possibly a leak on the suction side of the pump pulling in air.

Answer 3

check to see if you have a pipe leaking causing the pump to keep the well drawn all the way down thus sucking air. happened to me. a pvc hose run pipe was separated at the joint. the ground was very wet. dig it up, fixed it, and saved thousands chasing whatever...

Answer 4

Could be a bad foot valve combined with a leak somewhere that is allowing the water on the pump side of the check-valve up top to partially drain out. The pressure tank and water lines get a charge of air every time the pump starts. Last time I had this happen, the barb coupling on top of the submersible pump had a rust hole in it (shallow 32 ft well with black plastic discharge pipe).

Answer 5

Our setup has a vertical tank and the input pipe from the wellhead and the line out into the distribution system are both near the bottom of the tank. The contact points assembly was replaced and the check valve was replaced yesterday.

Today, the pump operated with greater efficiency, such that air was drawn into the tank, so much so that air began spitting out of the faucets and fixtures indoors and out. Until the leak in the pipe below the wellhead is fixed (pipe replaced), we have to shut down the system and bleed air from the top of the tank. The well casing extends to 170 foot depth.