A booster heater is almost always required with a high-temp dishwasher, which may or may not include the component with the purchase. Make sure the booster heater you select is sized correctly for your dishwasher. The machine's manufacturer should be able to tell you which size you need. Booster heaters increase water temperatures by either 40 or 70 degrees Fahrenheit. You should choose one that will get the incoming water available to it to the 180 degree minimum temperature for sanitization. So, 40-degree-rise booster heaters require incoming water that measures 140 degrees or hotter, while 70-degree-rise booster heaters must be supplied with water that is at least 110 degrees.