The automatic valve calibration process has a full automatic mode which performs a bladder valve calibration on a schedule. If one of these calibration procedures results in an error, this fault is displayed when you press on the frown face icon. You can continue to run the line with the pre-calibration values. The next time the machine is stopped for a few minutes, have a technician run the calibration process from within the Service Section of the touch screen. Running AVC in this manner will generate more specific information that can be used in the troubleshooting process