SUBJECT: Refrigeration Conversion from R744 (CO2) to R134a. REVISION: 01. MODELS: GIII venders with CO2 refrigeration. PURPOSE / BACKGROUND INFORMATION: The R744 (CO2) refrigeration unit is no longer available for purchase from Royal Vendors. CAMPER VAN & MOTORkingclima CONVERSIONS. VW camper conversion kits . Citroen Dispatch camper