Con, you mean: "DUMP" switch.......check ?
I don't have a clue, that is the checklist, I just copied it and posted same.
My real concern is the number two step on the checklist.
2 - OXYGEN USE, ............................................................ if necessary
You are going along at FL-250 and the Cabin above 10,000 warning light comes on and the checklist says, "Oxygen if necessary"?
It just makes me uncomfortable. The aircraft was certified that way, so obviously the authorities to be were okay with the way it was written.