As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED ACFT LOSS PRESSURIZATION DURING CLIMB OUT OF RDU AND PERFORMED AIR TURN BACK. MX INSPECTED AND FOUND LOOSE AND RESECURED THE NR 1 AND NR 2 PACK DUCTS FROM DUAL TEMP VALVE TO HEAT EXCHANGER. OPS CHECK SUCCESSFUL. ACFT WAS APPROVED FOR RETURN TO SERVICE.