Abstract: A diverter valve with a shutoff feature for usage in an aircraft environmental control system is disclosed. The valve has a housing that includes an inlet connected with a source of air, and first and second outlets spaced 90.degree. apart. The first outlet is connected with the ECS refrigeration pack, while the second outlet, which is at a 90.degree. angle with respect to both the inlet and the first outlet, is connected with a bypass line that bypasses the refrigeration pack and is connected with a heater inside the ECS. A gate internal to the valve housing is rotatable over a 90.degree. range of motion to connect the air from the source to either solely the first outlet, to both the first and second outlets, to solely the second outlet, or to neither the first nor second outlets, depending upon a desired temperature of the air provided to the cockpit or cabin of the aircraft.