As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED SMELL IN FLIGHT, WHICH DISSIPATED AFTER TURNING OFF THE COMBUSTION HEATER. MAINTENANCE INSPECTED AND FOUND THE HEATER PRODUCING BURNING SMELL AND NOT CYCLING OFF UNTIL ABOVE 310F. R&R CYCLING SWITCH WITH NO FURTHER DEFECTS NOTED.