As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: DEPARTED AUS, AFTER LEVEL OFF AT 24000 FT, FOUND WE COULD NOT COOL THE CABIN SUFFICIENTLY AND RETURNED TO AUS. REMOVED AND REPLACED HIGH STAGE REGULATOR PER JOB CARD 08L40036002. REMOVED AND REPLACED PRESSURE VALVE (AALA202207055589).