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 before refilling. 2. Attach the CGA320/W21.8 fitting to a standard commercial CO2 cylinder. 3. Disconnect the quick-connect fitting from the black adapter. Tighten the black adapter onto the CO2 cylinder. Ensure the adjustment knob on top of the black adapter is fully turned upward (in the highest position). Do not turn the knob downward during operation — doing so may depress the 6 mm valve pin and block CO2 flow. 4. Reconnect the quick-connect fitting. 5. For larger CO2 cylinders: position the cylinder horizontally or upside down, as some cylinders do not include a dip tube (siphon tube). 6. Slowly open the valve on the large CO2 cylinder. Opening too quickly may trigger the safety shut-off mechanism. Listen for gas flow to confirm proper operation. 7. Refill for approximately 15–20 seconds until the cylinder is fully charged. 8. Close the valve on the large CO2 cylinder. 9. Open the bleed screw to release any residual pressure. 10. Disconnect the adapter from the CO2 cylinder. Important Notes: 1. If liquid CO2 is present in the cylinder, invert or lay the CO2 cylinder horizontally to facilitate refilling — especially if the cylinder lacks an internal dip tube. 2. Ensure the SodaStream cylinder is empty and pre-chilled for optimal fill capacity. 3. Always open the CO2 cylinder valve gradually to avoid triggering the pressure relief mechanism 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 your cylinder’s configuration before purchase. If your CO2 cylinder has an RPV, select the “RPV Pushing Adapter” option when ordering.