As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PREFLIGHT CHECKS THE FLIGHT CREW REPORTED RECEIVING A ACM BLEED LEAK ANNUNCIATOR WHILE ON THE GROUND TWICE TRIPPING THE APU TWICE. THE MAINTENANCE VENDOR FOUND THE LEAK DETECTION ELEMENTS (TT015 AND TT116) TOUCHING IN THE KEEPER. REPOSITION ELEMENT AND CIGARETTE AND RESECURED. PERFORMED A SATISFACTORY OPS CHECK OF THE FIRE DETECT ELEMENT WITH NO DEFECTS FOUND. AIRCRAFT RETURNED TO SERVICE