C-Wire Adapter needed?

I have an old Bryant 90i variable speed furnace. I have 4 wires to my Honeywell Chronotherm III thermostat, R Y W G (no C), with a jumper between the R and Rc terminals. At the furnace control panel the R Y W and G wires are connected, and then there’s another 2-wire cable from somewhere inside the furnace connected to Y and C. Do I still need to install the C-Wire Adapter?

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Also, if I do need to install the C-Wire Adapter, do I disconnect the 2-wire cable connected to Y and C at the control panel, or keep it connected?

If you do not have an extra wire on your thermostat run then you will need to use the C wire adapter.
you only want to move the wires that go to your themostat, the other wires control your outdoor AC unit and need to stay on your furnace so that your A/C works properly and doesn’t start running when your heat is on.

Perfect! That’s what I kind of thought based on other comments I had read, but your diagram and notes are real nice. This’ll be a piece of cake. My main concern now is having the heat off while painting the wall after removing the old thermostat and getting the WYZE working. If worse comes to worse, I do know how to manually kick in emergency heat on my furnace. Thank you!

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