If you've changed the Wi-Fi router in your home you'll have to set up your Roost Smart Home devices again. For security reasons, Roost Smart devices originate all communication with the Roost Cloud. The only way our Roost Smart devices can communicate your Wi-Fi information is through the signal at set up.
You'll do this through the same set-up process you followed when your Wi-Fi Leak Detector was new.
However, first you need to reset the device to get it into set up mode. Please see our Help Center article: How do I reset my leak detector?
To set up a new Wi-Fi Leak Detector, on the home screen of the Roost App, tap the + button in the upper-right corner. Go through the same steps with the audio connection and connecting to the new Wi-Fi network.