A fluid valve incorporates a plunger with a fluid channel. The plunger is connected to a boss coupled to a diaphragm, this boss also includes a fluid channel and the plunger and boss fluid channels are in fluid communication. The boss fluid channel opens to the backside of the diaphragm in the valve cavity and permits substantially complete pressurization or evacuation of the volume behind the diaphragm in the valve. The substantially complete pressurization of the volume behind the diaphragm enables full closure of the diaphragm and improves contact of the diaphragm with the valve seat thereby improving performance of the valve.