Adjusting Air Volume Control Valve

I have a bladderless tank and need to adjust the air volume control valve, which is an Ametek one. Spec sheet indicates that the pressure relief valve is adjustable but was wondering how to go about doing this when the valve is already installed on the tank. I have too much pressure in the tank (due to some methane) and am getting sand in the lines. Suspect that the pressure relief on the AVC is set too high. Many thanx.

If you have the Air Release valve I am thinking of; there will be a screw slot in a little hollowed out plug at the bottom outside of the valve. That plug pushes in on the business end of a schrader valve spring. The reason is to keep the air in the tank under an adjustable pressure. This is so if you lose power, all the air won't excape from the tank leaving you totally out of water.

I use these Air Release valves in my Sulphur Removal System. We take the hollowed out plug out and throw it away. In our system which is removing sulphur gas, the plug tends to make the valve plug up sooner. Then the air starts going into the home spitting out of the faucets. If you turn this plug counter clockwise it will lower the pressure at which the air stops being released. Or remove it alltogether.

bob...