Whether you bought a high-temp dish machine without a booster heater or you're looking to replace one that failed, 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 depending on the volume of dishes you intend to wash in a given period of time. You should also make sure your incoming water is at the right temperature to be connected to the water heater booster you choose. A standard dishwasher booster heater provides a 40 degree F temperature rise to incoming water. Cooler water may require a 70 degree F rise to get it to the 180 degrees F necessary for chemical-free hot water sanitation.