Oregon Scientific Measuring Tools & Sensors - Page 5 - Recent Questions, Troubleshooting & Support

Check batteries in outdoor unit and try moving to closer to the base station.

I believe they ask you to press the reset button on the main unit first, but that may not be your problem. Double check the batteries to make sure they are installed correctly. If one of the batteries in the outdoor sending unit is in backwards, it will not send the outdoor data. On the indoor unit, there is typically one battery that is used for receiving the signal from the outdoor unit. If all of the batteries are in correctly but that one, you will see the display and the indoor temperature information, but the outdoor information will not be displayed. Also, make sure the units are close enough to transmit.

We are having the same problem