The mixing unit integral to “The Brain®” includes a thermistor, which is located in the outlet-water port. The thermistor is a resistive-temperature device, and its electrical resistance changes as the water temperature around it changes.
The valve contains a closed-loop controller circuit. This circuit compares the thermistor temperature to a predetermined temperature set point. If the outlet temperature deviates from the set point, the controller actuates an internal motorized proportioning mechanism, to change the hot/cold water blend and return the temperature to set point.
The outlet temperature set point can be adjusted 1 degree F at a time on the mixing valve, using an integral potentiometer.
A digital display on the face of the mixing valve constantly indicates “actual” temperature. A slide-open bezel on the face of the mixing valve changes the display to “set point” and reveals 1 degree at a time set-point adjustment potentiometer.