DL 5641 then DL 1655 at Boston
Cleveland → Boston → San Francisco
Timetable, Boston time
19:35DL 5641 from Cleveland at the gate
16:50DL 1655 to San Francisco leaves the gate
21 h 15 apart on the timetable, overnight
DL 1655 leaves 21 h 15 after DL 5641 arrives on the timetable: more than half a day, so not a connection we count.