An exemplary apparatus includes a switch, an arm, and a rod. The switch is housed by a housing and includes an actuating tab. The arm is housed by the housing and carries an arm magnet. The arm magnet includes first and second opposed surfaces and an edge surface. The rod carries a float and a rod magnet. The rod is movable between a first rod position and a second rod position at which the rod magnet is in the housing. As the rod moves from the first position to the second position, the edge surface of the arm magnet is configured to move across a facing surface of the rod magnet, thereby moving the arm from a first arm position in which the arm does not actuate the actuating tab to a second arm position in which the arm actuates the actuating tab.