Abstract: A device is disclosed for controlling the flow of refrigerant into a system and for controlling the application of a vacuum to evacuate the system via the same device prior to charging. The device is configured for controlling flow at the charging port to avoid loss of refrigerant from connecting lines. Piston operated valving internally mounted in a valve body controls the communication of refrigerant and vacuum sources to an outlet opening receiving a tubular charging port of the system to be charged. A pressure operated clamping pistion actuates gripping rings to secure the device to the charging port prior to both evacuation and charging and also acts to open the charging port valving as the fitting is clamped and sealed thereto. The outlet opening is defined by an end cap which is detachable from the fitting to allow use with different configuration charging ports by replacement with another end cap.