UA 571 then UA 1665 at San Francisco
Atlanta → San Francisco → Boston
Timetable, San Francisco time
09:29UA 571 from Atlanta at the gatealso CA 7243, VA 8403, NZ 9005
23:20UA 1665 to Boston leaves the gatealso VA 8306, NZ 9018
13 h 51 apart on the timetable
UA 1665 leaves 13 h 51 after UA 571 arrives on the timetable: more than half a day, so not a connection we count.