What was found
BURNING / SMOKE ODOR COMING FROM MID GALLEY HEATER WHEN TURNED ON TALKED TO CREW AND FILLED OUT SMOKE/ODOR REPORT. THEY REPORTED ALL NORMAL CRUISING CONDITIONS AND THAT THE ODOR EXTINGUISHED AS SOON AS THEY TURNED THE HEATER OFF AND DID NOT TURN IT BACK ON FOR THE REMAINDER OF THE FLIGHT. REMOVED AND REPLACED MID GALLEY DUCT HEATER REF AMM DMC-B787-A-21-45-30-01A-720A-A. NO LEAKS NOTED. RAN HEATER IN AIR MODE REF AMM DMC-B787-A-32-09-00-08A-950A-A. NO SMOKE OR BURNING ODOR NOTED. AFTER TESTING COMPLETED AIR MODE RESTORATION REF AMM DMC-B787-A-32-09-00-06A-521B-A. FOLLOWED REST OF FIM DMC-B787-A-21-20-F5-72A-421A-A AND DID NOT FIND ANY BURNING/SMOKE ODOR. OPS CHECKS GOOD.