I have an old honeywell 4-wire system. The original wires are shown in the photo. So I installed the 3rd gen Nest. Plugged the appropriate colored wires to G, Y1, W1. And 1st tried R to Rc. The app shows all wires connected correctly. Tested heat, It ran for 1 second then stopped. DIdn't work. No heat. No fan. So I then tried connecting R to Rh on the Nest. Same thing. I heat it turn on for 1 second, then it stopped. No heat. No fan. So then I re-installed my old honeywell thermostat, and its heating properly. So what's the problem? The other wires seemd connected fine (the tabs stay depressed). I dont know what to do? Any ideas? The error code shows a T04 which is just a general forced heating error code.
