It depends on if the unit was built with a dual voltage transformer. Are there four leads on the primary(voltage in) side of the power transformer? If there are: see if they are marked 1, 2 ,3, 4 or X1, X2, X3, X4. If so: disconnect the 2 and 3 leads from the lines, and tie them together. This will convert your primary to 230v(windings in series). If they are color-coded: you need a schematic or code chart to properly re-wire the x-former. If there are only two line voltage leads: You'll need a 230v x-former.
