What was found
AIRCRAFT WAS GROUNDED: OFCR AIRFLOW OFF LIGHT ILLUMINATED ABOVE FL 250. ATTEMPTED MULTIPLE RESETS IN COORDINATION WITH MOC INCLUDING FLIGHT DECK AIR COND. RESET L PACK TRIP AIR SET TO HIGH. DECESION MADE TO RETUN TO FIELD AND EMERGENCY WAS DECLARED AND AIRCRAFT LANDED OVERWEIGHT WITHOUT INCIDENT. DURING T/S FOUND OFCR SUPPLY SOV NOT OPENING ON GROUND W/ L PACKOFF, R PACK ON. R/R OFCR SUPPLY SOV IAW 21-29-30, ACCOMPLISHED ALL TEST, OFCR SOV OPENS IN CORRECT CONFIG. PRECAUTIONARY RELOADAD FRESH SOFTWARE ON P210 CCU REF AMM 24-09-00. OFCR AIRFLOW CHECKS GOOD ON GROUND.