A blower assembly (100) for a pneumatic transfer tube system (10) comprises a housing (102, 104) having an internal cavity (106) and first and second external ports (152, 154) communicating therewith. A movable plate (112) having first and second sides divides the cavity into two generally isolated chambers. A blower (110) having vacuum and pressure ends (212, 214) is mounted to the plate (112), with the vacuum end (212) on the first side and the pressure end (214) on the second side. The blower (110) when operating creates a vacuum chamber on the first side and a pressure chamber on the second side. A drive assembly (222) attached to the plate (112) moves the plate (112) between a first position wherein the pressure chamber is in communication with the first port (152) and the vacuum chamber is in communication with the second port (154), and a second position wherein the pressure chamber is in communication with the second port (154) and the vacuum chamber is in communication with the first port (152).