As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BOS-PHL - FLT 6433 - AFTER TAKEOFF, LEFT AIRVALVE LIGHT ILLUMINATED. AIRCRAFT DIVERTED BACK TO BOS AND LANDED WITHOUT INCIDENT. MAINTENANCE REPLACED THE LEFT ANTI-ICE START BLEED VALVE (P/N 0058T80P03, S/N COMD0506) AND THE BLEED AIR SHUTOFF VLV (P/N 5056T88P01, S/N AFX10598). AIRCRAFT WAS RETURNED TO SERVICE. (M)