third seal 365 provide a barrier on the top and bottom of the aperture 235 to prevent leakage of gas exiting the vent line 420 fig5 is a section view of an alternative embodiment of a valve assembly 500 and fig6 is a section view of the valve assembly 500 installed in a housing 600 the housing 600 of fig6 includes additional fluid paths formed therein hydraulic conduits 630 635 are formed in the housing 600 and serve to carry hydraulic power fluid from an upper end of the housing 600 to the longitudinal bore 645 formed in the housing 600 the lines intersect the bore 645 at a location ensuring they will communicate with the valve assembly 500 after it has been installed in the bore 645 and is retained therein with the retention means described with respect to fig4 also formed in the housing 600 is an internal gas line 640 providing communication between the upper end of the housing 600 and the bore 645 by providing hydraulic conduits 630 635 and gas line 640 internally within the housing 600 there is no need for separate hydraulic lines or a gas supply line to remain attached at an upper end of the valve assembly 500 as illustrated in fig6 the valve assembly 500 is installed in bore 645 with a selective connector or gripping tool 607 that temporarily retains the valve assembly 500 by gripping a fish.