A rotary coupler for directing a fluid flow between a supply of pressurized fluid and a fixture which is rotatable about a fixture axis and which has a manifold plate directing the fluid flow from a manifold inlet and a manifold outlet to a plurality of stations on the fixture positioned about the fixture axis. The coupler including a spindle including a base portion and a shaft portion and which extends in an axial direction from a mounting end on the base portion and a distal end on the shaft portion. The base has a mounting face and a securing arrangement configured to secure the mounting face to a manifold plate such that the mounting face sealingly engages the manifold plate. The shaft portion defines a coupler axis and has a shaft surface generally coaxial to the coupler axis and the shaft surface includes an annular pressure zone and an axially spaced annular tank zone. The spindle also includes an internal pressurized fluid passage and an internal tank fluid passage wherein the pressurized passage extends within the spindle between a pressurized face opening in the mounting face and a pressurized shaft opening in the pressure zone. The pressurized passage includes a check valve limiting flow from said face opening to said shaft opening. The tank passage also extends within the spindle between a tank face opening in the mounting face and a tank shaft opening in the tank zone. The mounting face includes an annular recess and the tank face opening is with this recess such that fluid flow reaching the recess is directed into the tank passage. The coupler further includes a hub with a shaft opening shaped to receive the shaft portion of the spindle such that the hub rotates about the shaft and the coupler axis, at least one of the hub and the shaft has an annular pressure zone channel in the pressure zone allowing the pressurized fluid to flow about the shaft in the pressure zone. In addition, at least one of the hub and the shaft includes an annular tank zone channel in the tank zone allowing the tank fluid to flow about the shaft in the tank zone. The coupler further including a seal separating the tank zone from the pressure zone and the hub has a pressure port and a tank port. The pressure port is the hub is in fluid connection with the pressure zone and the tank port is in fluid connection with the tank zone. The coupler further including a bearing arrangement between the spindle and the hub.