Abstract: A valve having an input and two outputs is provided with a stem extending radially from and pivotal about a transverse axis from a middle position to one end position directing flow from the input to one of the outputs and to an opposite end position directing flow from the input to the other of the outputs. A valve actuator assembly has a sleeve fixed to the valve and having a rim annularly surrounding and spaced from the stem and lying in a plane generally parallel to the axis and a handle fixed to the stem above the rim and forming a guide extending substantially parallel to the stem. A latch element having an outwardly projecting arm is displaceable in the guide between a rest position with the arm engageable with the rim and blocking displacement of the stem into the one end position and an actuated position unengageable with the rim and permitting displacement of the stem into the one end position.