As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LAS - SMOKE - ON GROUND CATERER REPORTED EXCESSIVE SMOKE COMING FROM APU AND A GATES AGENT REPORTED FLAMES COMING FROM APU. THE APU WAS SHUT DOWN, NO ECAM MESSAGE. APU WAS DEFERRED. MAINTENANCE REMOVED AND REPLACED THE FUEL DIVERTER IAW AIRBUS 320 AMM 49-32-12. OPERATIONAL CHECKS WERE GOOD. VENDOR CONFIRMED FAILURE. FOUND CHECK VALVE PISTON GROOVED. REPAIRED AND RECERTIFIED IAW CMM 49-32-07 REV.01.