A dishwashing appliance includes a tub defining a wash chamber. An inlet is defined in the tub and provides air flow into the wash chamber. A diverter disk is proximate the inlet and upstream of the wash chamber. The diverter disk is rotatable between a first position and a second position. The diverter disk permits air flow into the wash chamber via the inlet in a first direction when the diverter disk is in the first position and in a second direction when the diverter disk is in the second position.