This error means that the control is not seeing a valid reading from the light sensor. In most circumstances this is a sensor/wiring problem that needs to be addressed. Please see DOL’s Technical User Guide for some more information.
Check if there are other temperature sensors assigned to control that equipment group. A temperature sensor in a different room or an outdoor sensor could be incorrectly assigned to control for that group and is being added into the averaging ...
Because the temperature sensor is built into the heat mat, the temperature it measures may be different than the actual mat surface temperature. Use the Sensor Correction setting to adjust the IMC reading to match the temperature gun reading. The ...