charging waterlogged galvanized tank using air compressor

Sorry, can't seem to find this thread. Need to add air to my waterlogged galvanized tank. Prefer to use compressor rather than empty the tank.
IRC, the procedure is:

turn off power to the pump
open a spigot
at the schrader valve, add air to about ? 28# of pressure? (I have an 80gal tank)
turn on power to the pump
turn off spigot

yes, no, corrections?
any reason I should NOT use the compressor method?
thanks

Not to dwell on minutia, but with an open spigot you will never be able to put 28 PSI of air in the tank. The air will displace the water and then blow out the spigot.

Drain the tank, and then close the spigot. After that you can add more air if you want to have a precharge.

Don't use a compressor that uses oil. It must be oil-less.

Thanks LLigetfa. I sure didn't "remember correctly".
The problem is the valve below ground needs to be replaced. Its about 21ft down, so its about a $12 part, but $225 to have replaced. I'm trying to apply a bandaid till I get it fixed. Without dumping alot of water at the tank site, while getting the job done as quickly as possible.
Checked with my local service company. Sounds like I would need to turn off the power, open a spigot, let it drain, then use compressor to pump water out of the tank. Close the spigot, add about 15=20# pre-recharge. turn power on.
Why an oilless compressor?

I appreciate your help. I don't like draining the tank in the well house, and it takes a lot longer if I'm running a spigot. So time to pay up and schedule the repairs.

It is not imperative that you drain the tank, you just need to make room for the air. For example, you could just keep adding small amounts of air every time the pressure drops down close to kick-in and only add air until the pressure reaches the kick-out setting. Repeating that a few times will build up the air volume without dumping water from the tank. You can tell how much air there is by the sweat line. If the tank doesn't sweat, licking the side of it with a propane torch will show you the water level.

You don't want to put oily air in the tank, hence the use of an oil-less compressor.

Non-pro, just thinking. No experience in this.

Suppose you could put a fixed amount of air into the tank, rather than putting in an amount of pressure. So I am thinking you could charge up a 10 gallon portable air tank and inject the air into your big tank. Repeat as needed. You will need to be mindful of not putting in too much pressure to make the water go over maybe 80 PSI. I don't know if you have any bladder tank in your system. If not, initially you could get the pressure too high quickly, but that effect would reduce as you have added water to your tank.

If using a compressor as you described, maybe control a tap quickly so you can turn it off if you overdo the air. To avoid an accidental air blowout next to you, use an outdoor faucet with a hose connected to avoid a blow near you.
http://www.homedepot.com/p/Husky-10-Gal-Portable-Air-Tank-CT10H/202528456

I suspect the no-oil thing is because you don't want oil in your drinking water.

There is probably nothing wrong with the bleeder orifice down in the well. They usually fail in the open position when and if they fail. Your above ground check valve is probably not holding good, and/or the Schrader valve is plugged or has a cap screwed on it. The bleeder orifice down the well can’t let the water out unless the above ground check valve seals off good and the Schrader can let air suck in.

I wouldn’t pull anything until I tried a new check valve and Schrader.



The best way I have been able to explain how to “de-waterlog” a tank with a compressor is this.

Turn off the pump.
Open a faucet or several faucets.
Hook up the air compressor and let it fill the tank with air.
When the air starts coming out any of the faucets, shut off the compressor, close the faucets, and turn the pump back on.

I shut off the pump and drain it down to about 10 psi. Then fill to about 50 psi+ and turn the pump on. I run about 45 to 70 psi, and this give a bit of precharge and lessens the time between re- airing.

Or I have a tank with the schrader filler right in the center. I drain down to that level, and pump up to the cut in pressure before turning pump back on. But its all a PITA and I think Im headed to all diaphragm tanks. Awfully cheap on amazonia now.