So today I go on a call, older lady couldn't figure out how her stat worked, she just wanted the temp up for winter to heat. The battery's were dead so I changed them and set stat to hold, inside temp 77 set temp 67, for some reason in thinking the heat should be on and I'm turning stat down farther and wondering why the hell the heat won't kick on then ding the bulb goes off, duh maybe turn it up you idiot lol.