Follow the diagram for single phase, likely just a jumper.
7000w @ 240v is about 29a, X 1.25 is 36a, so #8 wire, 40a breaker.
I'd run 8/3 romex to a disconnect, then from the disconnect a piece of liquidtight flex to the unit with x2 no 8 t90 and a bond. Keep the romex protected from...