Abstract: A sprinkler for watering a fixed spray pattern includes a flow conduit having a nozzle coupled thereto. A filter screen is held in place beneath the nozzle. The filter screen engages against a poppet type valve member of a flow shut off valve to space the valve member away from a valve seat to permit water flow through the flow conduit when the filter screen and nozzle are in place. If the nozzle is removed, the filter screen can move far enough upwardly, or can itself also be removed, that the valve member closes to shut off flow through the flow conduit. The flow shut off valve is located at a fixed distance from a reference point in the top of the flow conduit to permit the same sized screen to open the valve regardless of the overall length of the flow conduit. A flush cap used initially on top of the flow conduit in place of the nozzle, i.e.