Some of the more common readings that indicate a sensor is malfunctioning include NANs (not a number) or unrealistic values such as a panel temperature reading of 500 degrees Celsius. If NANs occur, it is possible that there may be either programming or wiring errors. Double-check the setup, and contact Campbell Scientific for assistance if the issue continues. Depending on the sensor behavior, the sensor may need to be returned to Campbell Scientific for repair.