A pneumatic mixing valve is provided, which includes a housing that defines a first inlet, a second inlet and an outlet. The first inlet is coupled to a first fluid source and the second inlet is coupled to a second fluid source. The housing defines a first chamber and a second chamber. The pneumatic mixing valve includes a mixing system. The mixing system includes a piston that is movable by at least one of the first fluid and the second fluid. The housing defines a fluid passageway that extends from near the first inlet to the second chamber and the pneumatic mixing valve includes an actuator that is movable between a first position and a second position. In the first position, the fluid passageway is closed such the outlet is open, and in the second position, the fluid passageway is open such that the outlet is closed.