Honeywell model RTH6580; how to reconnect after connection failure “error message E02.” My Wi-fi password was changed on schedule and knocked this unit offline. This video shows how to reset thermostat to wi-fi setup mode. Details video next: https://goo.gl/1bgQMA Information normally only available through Honeywell tech support. If this helps you, you can donate to help create more DIY vids and shop Amazon using my affiliate link: http://amzn.to/1ROXZ44 No extra cost to you. Just click before you shop next time, or click now and save the Amazon start page. Thanks!