The Network Repair Mode setting is located in the Home Settings -> Flair Devices tab.
The goal of Network Repair Mode is to assist with pairing issues. When toggled on this mode allows end devices (Smart Vents and Sensor Pucks) to re-pair with a new Flair hub (Bridge or Gateway Puck).
Please note that there is a 30-minute timer and your system will exit Network Repair Mode automatically after 30 minutes.