As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE FLIGHT CREW REPORTED THAT DURING PRE-FLIGHT CHECKS THAT THE LEFT FORWARD FUEL SUMP VALVE WOULD NOT SPRING BACK CLOSED. THE MAINTENANCE TEAM REMOVED AND REPLACED THE DEFECTIVE SUMP VALVE (P/N 72D4X) OPS AND LEAK CHECKS SATISFACTORY. THE AIRCRAFT WAS RETURNED TO SERVICE.