What was found
PASSING 10000 FT, RECEIVED ECAM ALERT ROR EXCESS CABIN ALTITUDE, ALSO OBSERVED ECAM ADVISORY FOR EXCESS CABIN VERTICAL SPEED (APPROX 3800') CLIMB. TRIED CONTROLLING WITH MANUAL PRESS CONTROL COULD NOT STOP RATE OF CLIMB. DONNED OXYGEN MASKS DESCENDED TO 10000' AND RETURNED TO FIELD. INSTALLED NEW DEPRESSURIZATION VALVE IAW AMM 21-31-15-04-01. PERFORMED OPS CK OF 1 AND 2 PRESSURIZATION SYS AS WELL AS DEPRESSURIZATION VALVE AUTO AND MANUAL FUNCTIONS IAW AMM 21-31-00, PG 501. ALL TESTS NORMAL. OK FOR SERVICE.