As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE CLIMBING OUT. CREW RECEIVED A BLEED DUCT WARNING MESSAGE. CREW RAN THE QRH WHICH TOLD THEM TO SWAP TO THE OTHER PACK. OTHER PACK WAS ALREADY DEFERRED AND COULD NOT BE USED. CREW TURNED OFF WORKING PACK AND FLEW UNPRESSURIZED BACK. NO EMERGENCY WS DECLARED. ONLY ISSUE WAS IT BEGAN TO BECOME HOT IN THE CABIN BY THE TIME THEY LANDED. FOUND DUCT (P/N: GG670-80304-4) LEAKING. REPLACED DUCT.