A:Answer Hi Insearchof. Thank you for your question. All Bosch Dishwashers have a flow through water heater in their motors. In conventional dishwashers, water falls randomly onto a heater coil at the bottom of the appliances. These coils remain heated throughout the wash cycles, making them extremely hot. This often melts plastic items placed on the bottom racks. However, the Bosch dishwashers' flow-through water heater is confined, preventing its coils from damaging household items and ensuring water is heated more thoroughly. While traditional dishwashers only heat portions of the water that lands onto the coils, Bosch dishwashers heat 100 percent of the water that passes through its heating chamber between tightly spaced coils.