Why does my product screen display LLL.LL? L Why does my product screen display LLL.LL? If the temperature of the environment is within the thermometers’ or hygrometers’ measuring range, this error will occur if the probe is disconnected or damaged. Post navigationPrevious post: Smart Alarm™Next post: Why is it blank, faint, or giving erratic readings? Leave a Reply Cancel replyYou must be logged in to post a comment.