As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE AIRPLANE TOOK OFF FROM KACG AND THE CABIN HEAT WAS NOT ABLE TO BE REGULATED. THE CABIN TEMPERATURE CONTINUED CLIMBED SO THEY HAD TO GO BACK TO KACG. THERE WASN'T PRESSURIZATION PROBLEMS. THE PILOTS HAD TO BURN OFF FUEL AND FLEW FOR APPROXIMATELY 45 MINUTES. THEY WERE ABLE TO GET THE TEMPERATURE DECREASE WHEN THE LEFT BLEED AIR WAS TURNED OFF. AFTER TROUBLESHOOTING WE FOUND THAT THE EMERGENCY PRESSURIZATION VALVE WAS STUCK IN EMERGENCY. THIS MADE THE BLEED AIR TEMPERATURE TO BE UNREGULATED COMING INTO THE CABIN.