A valve (200, 700) comprising: a fluid block (240, 740) that comprises a process fluid inlet and a process fluid outlet, a valve plate (250, 750) that comprises an actuation fluid cavity (280, 780), and a valve assembly disposed in an assembly cavity (210, 710) formed by said fluid block (240, 740) and said valve plate (250, 750); a valve cavity (270, 770) in said assembly cavity (210, 710), said valve cavity (270, 770) formed between a diaphragm spacer (230, 730) and a valve seat in said assembly cavity (210, 710); a diaphragm assembly (219, 719) in said assembly cavity (210, 710), said diaphragm assembly (219, 719) comprises a diaphragm (220, 720) and a boss (224, 724), said diaphragm assembly (219, 719) secured by said diaphragm spacer (230, 730) and said fluid block (240, 740) in said assembly cavity (210, 710) and fluidly separating said valve cavity (270, 770) into a process fluid side and an actuation fluid side, characterised by a plunger (260, 760) in said assembly cavity (210, 710), said plunger (260, 760) comprising a plunger cavity (268, 768) formed in a plunger stem (262, 762), and a plunger fluid flow passage (266, 766) in said plunger (260, 760), said plunger fluid flow passage (266, 766) fluidly connecting the actuation fluid cavity (280, 780) and plunger cavity (268, 768); said boss (224, 724) being coupled to said plunger stem (262, 762) through a central passage of the diaphragm spacer (230, 730), said boss (224, 724) comprising a fluid flow passage (226, 726) formed therethrough that provides fluid communication between said actuation fluid cavity (280, 780), said plunger cavity (268, 768), and the actuation fluid side of said valve cavity (270, 770). a fluid block (240, 740) that comprises a process fluid inlet and a process fluid outlet, a valve plate (250, 750) that comprises an actuation fluid cavity (280, 780), and a valve assembly disposed in an assembly cavity (210, 710) formed by said fluid block (240, 740) and said valve plate (250, 750); a valve cavity (270, 770) in said assembly cavity (210, 710), said valve cavity (270, 770) formed between a diaphragm spacer (230, 730) and a valve seat in said assembly cavity (210, 710); a diaphragm assembly (219, 719) in said assembly cavity (210, 710), said diaphragm assembly (219, 719) comprises a diaphragm (220, 720) and a boss (224, 724), said diaphragm assembly (219, 719) secured by said diaphragm spacer (230, 730) and said fluid block (240, 740) in said assembly cavity (210, 710) and fluidly separating said valve cavity (270, 770) into a process fluid side and an actuation fluid side, characterised by a plunger (260, 760) in said assembly cavity (210, 710), said plunger (260, 760) comprising a plunger cavity (268, 768) formed in a plunger stem (262, 762), and a plunger fluid flow passage (266, 766) in said plunger (260, 760), said plunger fluid flow passage (266, 766) fluidly connecting the actuation fluid cavity (280, 780) and plunger cavity (268, 768); said boss (224, 724) being coupled to said plunger stem (262, 762) through a central passage of the diaphragm spacer (230, 730), said boss (224, 724) comprising a fluid flow passage (226, 726) formed therethrough that provides fluid communication between said actuation fluid cavity (280, 780), said plunger cavity (268, 768), and the actuation fluid side of said valve cavity (270, 770).