As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAH - FLIGHT 2160, THE CREW REPORTED THAT THE PACK TWO VALVE WOULD NOT OPEN AFTER TAKEOFF AND COULD NOT GET IT OPEN AFTER MULTIPLE RESETS. THE AIRCRAFT RETURNED TO IAH WHERE IT LANDED WITHOUT INCIDENT. MAINTENANCE INSPECTED THE AIRCRAFT AND RE-SECURED A DUCT ON THE NR 2 PACK DUAL TEMP CONTROL VALVE, OPERATIONAL AND LEAK CHECKS COMPLETED WITH NO DEFECTS, AND THE AIRCRAFT WAS APPROVED FOR RETURN TO SERVICE.