I can't find any information in our manual that informs you where you would see a low battery condition on the remote sensor unit. Secondly, if we were to replace them as a preventative measure do you lose all of your data on the house unit?
I have attached a photo of the front of the display to show you where the low battery indicators will appear when your sensor or your display batteries are low. Those icons will only appear if your batteries are low and will not be there at all times. If you are replacing the batteries into the outdoor sensor, or in the display, you can leave the display plugged into the AC adapter to prevent any history from being lost. If you have any other questions, please let us know.