Replacing 2 Hunter thermostats with a Honeywell RTH9580 Wifi. Neither unit has a C wire - I'm comfortable with the upstairs high efficiency unit, but the downstairs older unit has thrown me for a loop.
The Hunter has cables connected to G-RH-Y-W, with proper color coding. There was a spare wire - so no problem, go downstairs, connect to C, and I'd have my 5 wires, good to go. But... when I got downstairs I found the "Y" connected to "C" on the unit, and the Y terminal had no wiring. I bought the house this winter, so its never run the A/C. I'm beginning to question what would happen if I flipped the switch to COOL!
There are secondary wires jumpered off that run to the compressors - but I'm not understanding how to fix the wiring. Can I just move the wire connected to "C-Y" to "Y-Y" and use the spare wire to connect to "C-C"? Or is there some reason a unit would be wired to "C" on the unit and "Y" on the thermostat??