What was found
IAH - AIR TURN BACK - FLT 0103 - ON DEPARTURE OUT OF IAH EN ROUTE FOR LAS RECEIVED UPPER ECAM MESSAGE FOR AVIONICS VENT FAULT, EXTRACT VALVE INDICATED FULL OPEN NOT ALLOWING AIRCRAFT TO PRESSURIZE, TURNED BACK TO IAH AND LANDED WITHOUT FURTHER EVENT. MAINTENANCE REMOVED AND REPLACED SKIN AIR OUTLET VALVE IAW T/C R2A211301, OPERATIONAL CHECK WAS GOOD. FUNCTIONAL TEST OF SKIN AIR VALVE SN 1175 CONFIRMED REASON FOR REMOVAL FINDING THAT ACTUATOR UNIT WAS JAMMING CAUSING TORQUE LIMITER TO SLIP. REPLACED ACTUATOR AND RE-ACCOMPLISHED FUNCTIONAL TEST IAW CMM 21-26-53 REV. 6.