From the Manufacturer --------------------- The Tempra® Plus is the most technologically advanced tankless water heater available on the market today. Advanced Flow Control is exclusive to the Tempra® Plus and ensures a constant temperature output no matter how great the hot water demand is. Advanced Flow Control technology works by automatically adjusting the flow of water to eliminate unpleasant temperature fluctuation. What that means to you is a consistently satisfying experience every time, all the time !