What was found
IAH - FLIGHT 2924, DURING PREFLIGHT INSPECTION THE CREW REPORTED A BURNING SMELL FROM BOTH COFFEEMAKERS. MX PLACED THE COFFEEMAKERS ON NEF NR GL01 D CTL NR 160100, AND THE ACFT WAS RETURNED TO SERVICE. ON 12/14/08 THE DISCREPANCY REPEATED AND MX INSPECTED THE COFFEEMAKERS, FOUND THEM TO BE DIRTY ON THE HEATERS, CLEANED THE HEATERS, OPS CHECKED WITH NO DEFECTS, REMOVED THE NEF, AND THE ACFT WAS APPROVED FOR RETURN TO SERVICE.