Abstract: A sprinkler having an output orifice through which water operatively flows, includes a flush cap adapted for movement relative to the output orifice from a free position wherein the cap is disengaged from the sprinkler, to a locked position wherein the cap is generally fixed to the sprinkler and substantially covers the output orifice. The flush cap in the free position is angularly displaced in a single plane from the flush cap in the locked position. A deflector, disposed at an obtuse angle to the axis of the cap, biases the cap to the locked position during a flushing operation. Pulling grip portions of a handle also biases the cap to the locked position. An associated method includes the step of tilting the flush cap in a single plane in order to engage the sprinkler in the lock position.