As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TRIP NR 1124081 CREW REPORTED UNCONTROLLABLE COCKPIT HEAT AND THE ODOR OF SOMETHING BURNING. AIRCRAFT RETURNED TO FIELD. MAINTENANCE TROUBLESHOT THE SYSTEM AND FOUND THE COALESCER SOCK EXTREMELY DIRTY. SUBSEQUENT OPERATIONAL CHECKS PROVED SATISFACTORY.