What was found
APPROX. 5 MINUTES AFTER FINISHING ECS 2 VALVE FAIL QRH, A GRADUAL LOSS OF CABIN PRESSURIZATION STARTED. CABIN ALTITUDE WAS ROUGHLY 3000FT. ROUGHLY 2-3000FPM CLIMB IN THE LOSS OF PRESSURIZATION, RATE READING WAS IN THE RED. THIS OCCURED WHILE AT 280+KTS, ROUGHLY AROUND 29,000FT. WE WERE ABLE TO DESCEND RAPIDLY TO 10,000FT. ONCE LEVEL AT 10,000FT, CABIN ALTITUDE EQUALED 10,000FT, MASK DID NOT DEPLOY. CABIN DELTA P AT 10,000FT WAS 0.0, CAB ALTITUDE HI CAS CAME ON, WE CONTINUED A DECENT BELOW 10,000FT, ACCOMPLISHED QRH PROCEDURE. CORRECTIVE ACTION; REPLACED THE RH FCSOV AND COMPLIED WITH OPS AND LEAK CHECKS WITH NO FAULTS. WORK DONE WITH REFERENCE TO EMB505 AMM 21-21-01.