What was found
IAH - FLIGHT 2843, THE CREW REPORTED PAC1-2 VLV CLSD MSGS WITH THE NR 1 PACK ON MEL. THE ACFT RETURNED TO IAH WHERE IT LANDED WITHOUT INCIDENT. MX R&R A BLOWN DUCT ON THE NR 2 PAC, OPS TESTED WITH NO DEFECTS, AND THE ACFT WAS APPROVED FOR RETURN TO SERVICE.