As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT FL340 WITH SINGLE PACK DISPATCH CABIN CONTINUED TO CLIMB TO 500FPM AND IN AUTO ONE. VALVE DID NOT SHOW FULLY CLOSED, 7 PSID CBN ALT 10000. MANUALLY CLOSED VLV IAW QUICK REF CKLIST, CBN REACHED 13000 FT. DESCENT AND RETURN TO CVG. FOUND CLAMP BROKEN ON RT PACK OUTPUT DUCT. REPLACED BOTH CLAMPS. PRESSURIZED ACFT. ALL CKS NORMAL.