What should I be adjusting the initial AVC psi on a drianback tank to when I first install it?

[PaulTheBall]

I have always been told that, after installing the avc I should add air to 20 psi, open the air vent thing to just before air starts hissing out, then turn the system on and let water fill up the tank the rest of the way. Reading the little bit of instructions I can find seems to support this, but I saw the other day a diagram that showed the cut on\cut off pressure at 30\50.

So on a 40\60 switch should I be adding air to 30 psi, then going through the other steps?

 

[Valveman]

You don't really have to pre-charge an air over water tank system. It does make the tank hold more water, but won't stay over-charged like a diaphragm tank will. The AVC will let out air until the water level reaches the float. You would need to fill the tank with water until the AVC stops spurting air and shut off the pump. Then you could charge up the tank to about 30-35 PSI with the 40/60 switch. If you don't have sulfur or iron and need to aerate the water, a diaphragm style tank is the best way to have a pre-charge.

 

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[Reach4]

If using an air over water tank, instead of a diaphragm tank, something needs to be regularly adding air. Then the AVC expels the excess air.

Typically, that air enters via a snifter valve, to replace water drained by the drain back valve in the well.