What was found
CLT - FL 645 - ON CLIMB-OUT FROM CLT, CREW WAS UNABLE TO PRESSURIZE A/C. AFTER PERFORMING CHECKLIST AND CLIMBING TO 7,000 FT, CREW ELECTED TO RETURN TO FIELD AT CLT. NO EMERGENCY WAS DECLARED AND THE FIGHT LANDED W/O FURTHER INCIDENT. MX FOUND THE RT PACK WATER SEPARATOR ASSY COLLAPSED AND THE GROUND AIR CHECK VLV LEAKING. REPLACED WATER SEPARATOR ASSY (P/N 183010-4) AND REMOVED DEBRIS FROM MIX MANIFOLD AND CHECK VLV. FOUND HOLE IN RT PACK TURBO FAN DUCT AND LT RECIRULATION FAN FODDED. REPLACED DUCT (P/N 69-49792-5) AND FAN (P/N 645405-1). ALSO, FOUND RT 35 DEGREE CONTROL VLV STICKING AND 35 DEGREE CONTROL BOX DEFECTIVE. REPLACED VLV (P/N 321942-1) AND CONTROL BOX (P/N 607510-3). ACCOMP PRESS SYS OP CH