the check valve 38 on its inlet side 86 and allows fuel to flow around the outsides of the check valve 38 and through the hydraulic cavity 90 to the right of the check valve 38 the check valve 38 is biased to a closed position by a spring 91 and prevents fuel from back flowing to the underground storage tank when the stp 10 is serviced the stp 10 is shut off and the service personnel must remove the packer 18 to pull out the pump in the hydraulic cavity 20 for servicing however after the stp 10 is turned off there is still residual pressure trapped in the pipeline when the check valve 38 is closed since fuel will no longer flow to keep the check valve 38 opened there is a differential pressure between the outlet side 88 of the check valve 38 which is hydraulic cavity 90 and atmosphere if the check valve housing 36 is removed by service personnel to gain access to the check valve 38 the pressure build up on the outlet side 88 of the check valve 38 will equalize with atmosphere or the pressure on the outside the stp 10 and fuel will possibly spill outside of the manifold 19 and stp 10 to the environment and possibly make contact with the service personnel the present invention provides the ability to depressurize the outlet side 88 of the check valve 38 before the check valve 38 is serviced by actuation of a lock down screw 92 which has not been done before the present invention depressurization of the check valve 38 is accomplished by placing a tool inside receptacle 94 and rotating the receptacle 94 which lowers.