As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED EMERGENCY PRESSURIZATION SYSTEM CAME ON DURING TAKEOFF WITH AIR CONDITIONING FAIL ANNUNCIATOR LIGHT ILLUMINATED. TROUBLESHOT SYS IAW MM21-00-00. FOUND RT PRESSURE REGULATING/SHUT-OFF VALVE (PRSOV) HAD FAILED, ALLOWING FULL BLEED AIR VOLUME THROUGH AT ALL THROTTLE SETTINGS. REPLACED PRSOV WITH OVERHAULED VALVE IAW MM21-10-00. ENVIRONMENTAL SYS OPERATIONAL CHECKS NORMAL ON GROUND RUN-UP. MAINTENANCE RECORDS UNAVAILABLE.