AC 4121 then UA 755 at San Francisco
Ontario → San Francisco → Washington
Timetable, San Francisco time
17:50AC 4121 from Ontario at the gate
12:45UA 755 to Washington leaves the gatealso CA 7313, NZ 9162
18 h 55 apart on the timetable, overnight
UA 755 leaves 18 h 55 after AC 4121 arrives on the timetable: more than half a day, so not a connection we count.