The range or distance of the Wi-Fi signal is determined by your router. Check your router's manual for additional information. It is possible that your thermostat is unable to find or maintain reliable connectivity to your Wi-Fi network because of a poor signal from the router. For example, most homes have “dead spots” where Wi-Fi signals are unreliable. This can be fixed by moving your router to a better location or by setting up a repeater- a device that will pick up and rebroadcast the wireless signal from your router to your thermostat. You can either purchase and install a Wi-Fi repeater, or configure an additional router to serve as a repeater. Most standard routers can be configured as a repeater.