What was found
DURING CLIMB-OUT CABIN ALTITUDE WAS NOTED AT 7,500' CLIMBING THRU FL220 WITH BOTH PACKS ON AND CARGO HEAT OUTFLOW VALVE CLOSED. SWAPPED BLEEDS WITH NO EFFECT. ATTEMPTED STANDBY MODE AS WELL AS MANUAL MODE WITH NO EFFECT. OUTFLOW VALVE WAS FULLY CLOSED IN DC MODE WITH NO EFFECT. TROUBLESHOOTING PRESS PROBLEM. ON BLOCK IN FOUND ALL DOORS SECURE AND PER CREW DE-BRIEF PACKS APPEARED TO BE OPERATING NORMALLY. FOUND RT PACK VALVE FAILED CLOSED. REMOVED AND REPLACED RT FWD PACK VALVE IAW MM 21-55-071-0. PRESS OPS CK GOOD PER MM 21-31-000-5.