FR 3976 then DL 155 at Dublin
Barcelona → Dublin → Boston
Timetable, Dublin time
19:00FR 3976 from Barcelona at the gate
11:55DL 155 to Boston leaves the gate
16 h 55 apart on the timetable, overnight
DL 155 leaves 16 h 55 after FR 3976 arrives on the timetable: more than half a day, so not a connection we count.