A:AnswerOpie says: Yes, it works with a two wire system but you will have to run two more wires to the backplate from an external transformer (Amazon sells them for about $15). The instructions with the T9 show how to wire this 2 wire plus power setup. The backplate even has a special switch you manually set for this 2 wire system. This is not using the "C" wire adapter device, which is not useful for two wire system. See instructions.
A:AnswerThe T9 thermostat works efficiently with the wi-fi sensors that is packaged with the T9. There is no option in the thermostat settings to sync with existing wired sensors.
A:AnswerYes, you do. You could buy the one without the extra sensors for a little less, but you'd still need 2 theromstats. The extra sensors are very nice though.
