What was found
WHILE ON CLIMB OUT WE NOTICED A BURNING SMELL IN THE FLIGHT DECK ACCOMPANIED BY HIGH COCKPIT TEMPERATURE. SHORTLY AFTER WE RECEIVED THE DUCT 1 OVERTEMP YELLOW CAS MESSAGE. THE ECS SYSTEM SYNOPTIC PAGE SHOWED A YELLOW HX VALUE FOR THE LEFT SIDE AT 320°F. WE ACCOMPLISHED THE QRH PROCEDURE BUT THE CAS MESSAGE NEVER CLEARED IN THE ONE MINUTE ALLOTMENT DURING EACH QRH DECISION TREE. DUE TO THE BURNING ODOR REPORTED BY PILOTS, MCC REQUESTS THAT COCKPIT TEMP MODULATING VALVE BE REPLACED. REMOVED TEMP MODULATING VALVE & INSTALLED REPAIRED TEMPERATURE MODULATING VALVE P/N 1300330-11 S/N 1041. PERFORMED OPS CHECK, OPS CHECK OK. OBSERVED NO BURNT OR ABNORMAL SMELL. REF AMM 21-61-02.