a positive shutoff device is provided for a connection point of a refrigeration system . the connection point includes a manually - actuatable valve that permits charging and testing of the system . the device includes a first fitting engagable with the connection point and having a raised actuator that actuates the manually - actuatable valve when the first fitting engages the connection point , and a shutoff valve having a first end coupled to the first fitting and a second end coupled to a second fitting , the shutoff valve is operable in a closed position to prevent flow therethrough and an open position to permit flow therethrough , so that the refrigeration system may be charged or tested by connecting equipment to the second fitting and opening the shutoff valve , and the connection point may be positively shut off to prevent leakage of refrigerant through the connection point by closing the shutoff valve .