What was found
CLIMBING THROUGH FL270 NOTICED CABIN ALTITUDE AT 8000 FT AND CLIMBING. INITIATED LOSS OF PRESSURIZATION PROCEDURES. COULD NOT REGAIN CONTROL OF CABIN. INITIATED EMERGENCY DESCENT. THROUGHOUT PROCEDURES OUTFLOW VALVE INDICATED FULL CLOSED IN ALL POSITIONS (AUTO, STBY, A/C MAN, D/C MAN). EN ROUTE TO CVG AT 10000 FT A PRESSURIZATION SURGE AND CABIN BEGAN DESCENDING AT GREATER THAN 2000 FT/MIN. REPLACED EQUIP COOLING VALVE AND CARGO HEAT VALVE PRESSURIZED A/C CKS OK.