As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT 726, BWI - BOS. AIRCRAFT PERFORMED AN AIR TURN BACK TO BWI, BLEED 1 OVERPRESSURE MSG APPEARED ON CLIMB AFTER TAKEOFF. RAN QRH PROCD, MSG RETURNED. DISPATCH ADVISED RETURN TO BWI; ACCOMPLISHED FIM TASK 36 14 00 810 867A. REMOVED AND REPLACED LH BLEED OVERPRESSURE SWITCH AS NEEDED. IAW AMM 36 14 02. OPS CHECK GOOD LH ENG NEEDS A IDLE CHECK RUN PER MCC. ACCOMPLISHED SATISFACTORY GRND RUN IDLE CHECK ENG1 BLEED ON APU BLEED OFF. NO FURTHER FAULTS WERE NOTED AND ACFT IS OK FOR CONT SERVICE.