As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
L BLEED PRSOV SHOWS CLOSED ON AIR SUPPLY MAIN T, BLEED LOSS WING L, BODY L, BLEED LEAK L STATUS MSG'S AND L PACK INOP. CREW HEARD POP JUST BEFORE MESSAGES APPEARED. RETURNED TO IAD AND LANDED OVERWEIGHT. *S/D* FOUND LT HEAT EXCHANGER TORN OPEN AT PRIMARY INLET DUCT SEAM WELD. REPLACED LT HEAT EXCHANGER PART NUMBER 810208-1. UNDER INVESTIGATION BY THE MANUFACTURER.