Abstract: A connection system for carrying a refrigerant may provide a hybrid redundancy in sealing a refrigerant flow from the surround system environment. The connection system may include a first sealing ring of a first type and a second sealing ring of a second type positioned downstream from the first sealing ring. In some embodiments, the first sealing ring may be in a groove positioned around the outside diameter of a male fitting. The second sealing ring may be positioned at an interface between the male fitting and a female fitting. In some embodiments, flanges of each fitting define the interface so that the second sealing ring may be positioned between the flanges of each fitting. The second sealing ring may be selected from a material that has a wider range of operating temperature than the first sealing ring so that in the event of failure in the first sealing ring, the second sealing ring may prevent leakage.