Abstract: Two embodiments (FIGS. 1+ & FIGS. 5+) of a double, by-pass valve system for a closed refrigerant system allowing its safe servicing, the first being included in the original manufacturing of the compressor unit in the refrigerant exit line of the compressor (FIG. 4 ) and the second installed as a retro-fit on the compressor unit and provided "in-line" in the liquid refrigerant line. In the first a double valve body with a transverse bore through a main shut-off valve allows the flow of refrigerant to pass or be shut down to the rest of the system, while a secondary, access port with a transverse bore intersects the main flow valve on the upstream side of the seats by means of a manifold bore, providing a by-pass passageway to an access connection (minus a depressible valve core or "Schrader" valve) for a refrigerant hose to connect to the manifold charging gauges, allowing communication with the closed refrigerant system.