What was found
(CAN) ON POSITIONING FLIGHT, IN CRUISE AT 37 000, ECAM WARNING CABIN SAFETY VALVE OPEN, FOLLOWED BY CABIN PRESSURE EXCESSIVE, CABIN ALTITUDE . FLIGHT CREW PERFORMED EMERGENCY DECENT AND DIVERTED. ON LANDING, OUTFLOW VALVE HAD TO BE OPENED MANUALLY TO DEPRESSURIZE AIRCRAFT. OUTFLOW VALVE REPLACED AND SYSTEM CHECKED SERVICEABLE.