Refilling Adapter Kit for SodaStream Quick Connect W21.8 to CO2 Tank How it works: 1. Chill the SodaStream cylinder in the freezer for 1 hour. 2. Attach the CGA320/W21.8 fitting to a commercial CO2 cylinder. 3. Disconnect the quick-connect fitting from the black adapter, then securely tighten the black adapter onto the CO2 cylinder. Ensure the knob on top of the black adapter is fully turned upward (do not turn it downward — this would depress the 6 mm valve pin and close the valve, preventing CO2 flow). 4. Reconnect the quick-connect fitting. 5. For larger CO2 cylinders: position the cylinder upright, upside down, or horizontally, depending on design. Note that some cylinders do not include a dip tube (siphon tube). 6. Slowly open the valve on the CO2 cylinder. Opening too quickly may trigger the safety shut-off mechanism. Listen for gas flow to confirm proper operation. 7. After approximately 15–20 seconds, the SodaStream cylinder is fully charged. 8. Close the valve on the CO2 cylinder. 9. Open the bleed screw to release any residual gas. 10. Unscrew the adapter from the CO2 cylinder. Important notes: 1. If liquid CO2 is present, invert the CO2 cylinder during refilling if the cylinder lacks a dip tube. 2. Ensure the SodaStream cylinder is empty before refilling. Pre-chilled cylinders achieve optimal fill levels. 3. Open the CO2 cylinder valve very slowly to avoid triggering the safety valve (6 mm pin) on the SodaStream cylinder. 4. This adapter is not compatible with RPV (Residual Pressure Valve) systems. Some RPV valves can be removed using a hex wrench — please verify compatibility before ordering. If your CO2 cylinder has an RPV, select the “RPV Pushing Adapter” option when placing your order.