CO2 filling stations fill bulk CO2 tanks that come equipped with dip tubes. The CO2 tank screws into the station, and a hose is attached. The tank is placed on a scale that tracks the amount of CO2 filling the tank. Once the tank is filled to capacity, it is removed.
Before using a CO2 filling station, ensure that the station's ball valves are closed and the adaptor's pin is fully extended. The O-ring on the CO2 tank must be in working order, as it screws on to the fill station's adaptor. The sound of air moving from the CO2 tank into the fill station hose may be heard.
Open the ball valve that is farthest from the fill station's main valve. If the tank is already chilled, drain any air left in the CO2 tank; if it is not, chill the tank by closing the ball valve and opening the fill station's main valve. Open the valve closest to the main valve for four seconds, and then close it. Close the main valve and reopen the valve farthest from it. Drain the air in the tank before continuing, and shut all valves.
Place the empty CO2 tank on the scale, and zero the scale's display. Reopen the fill station's main valve and the valve closest to it. Close the valve when the scale measures the maximum capacity of the CO2 tank. Close the main valve, unscrew the pin, and reopen the valve farthest from the main valve to remove the leftover CO2 from the hose. Remove the CO2 tank; it is ready for use.