UA 2647 then DL 5665 at Boston
San Francisco → Boston → Richmond
Timetable, Boston time
16:49UA 2647 from San Francisco at the gate
15:23DL 5665 to Richmond leaves the gate
22 h 34 apart on the timetable, overnight
DL 5665 leaves 22 h 34 after UA 2647 arrives on the timetable: more than half a day, so not a connection we count.