I have a Trane XB80 and I installed a First Alert Smart thermostat a few years ago. I like Wyze products and decided to upgrade. I found out when I was installing the First Alert that I was missing a wire for the First Alert thermostat so the instructions said to jumper the G and Y terminals as my picture shows. I folllowed the Wyze instructions to use the C adapter and the thermostat did not power on. I tried leaving the furnace the way it was wired with the First Alert thermostat and the Wyze thermostat still would not power on. Any ideas?
what do the wires at the thermostat look like? and, do you have a clearer image of the furnace wires?
It should be powering up. You don’t have the C adapter installed on the furnace, but you shouldn’t need it, as you appear to have a spare grey wire that you could use for C. If you gently pull on the wires at your thermostat, you should find the grey and black wires (that are twisted around your thermostat cable in the furnace) in the wall.
You should re-attach the green wire to G on both sides and remove that jumper between G and Y.
Is there a fuse on your furnace board? Perhaps it was blown while you had the wires disconnected. Furnace fuses generally look like car fuses.
Thanks, I wired back up my old thermostat and that didn’t work. Was looking for the fuse to see if I blew it and found a blue wire disconnected from what looked to be a transformer. Checked the wiring diagram on the furnace cover and verified that blue wire needed to be connected to the transformer. Now i have heat 
Will install the Wyze thermostat this weekend!
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