A pipeline flow meter orifice fitting includes a first body, a flow bore through the first body, a chamber in the first body adjacent to the flow bore, an orifice plate supported in alignment with the flow bore by an orifice plate carrier, wherein the orifice plate carrier is exposed to the chamber and divides the flow bore into a first region to one side of the orifice plate and a second region to the other side of the orifice plate, a second body coupled to said first body, a first flow path fluidicly coupling the first region and the chamber through the second body, and a second flow path fluidicly coupling the second region and the chamber through the second body. In some embodiments, a three way valve is mounted on the first body, the three way valve selectably actuatable to open a first flow path between the first region and the chamber or a second flow path between the second region and the chamber.