I have a Bryant 94s Evolution HVAC system, I struggled for hours to play with It and was looking for insight.
What I’ve done.
I have 2 sets of ABCD wires, one to the thermostat and a second to ?ac compressor?. I took the set that goes to the Thermostat and wired R/G/W/Y/C and put those on the board. The second set which I’m assuming goes to the AC compressor outside I left in the green ABCD plug. I have heat, I can’t tell if the blower is pushing air as It should though. Further more I can not seem to get the AC to kick in and head the fan running, any help would be great !
To get proper help, you should post a picture of both your thermostat wiring showing the letters of the contacts they are connected to, and the same thing on the furnace control board that those wires connect to.
Then maybe someone like @speadie can make sense of that, and offer some suggestions.
ABCD wiring is for a communicating system. the user probably needs to tell the system that the thermostat is in standard non-communicating mode with a dipswitch. Unfortunately, they didn’t leave a model or serial number, so I can’t pull up the correct manual to figure out which switch it would be.
With these bryant systems, you have to convert the whole run to the same style of wiring. This means if you are using R/Y/C/W in the air handler and thermostat, it must also be run in that way to the outdoor unit. It should be possible to use the existing wires, just remove the plug connector from both ends and connect the same color wire to the same terminal on both sides, ex: if there is a red wire, connect it to R on both sides, if there is a blue wire, connect it to C on both sides, etc, You’ll want to connect the following wires: R, C, Y1, Y2. W1 is normally used when the coils are in defrost only, to help melt the ice off the inside coils faster, but it shouldn’t be strictly necessary, although if you wanted to run an extra wire for it, your cooling in humid weather would be better.
So I had a HVAC friend come help. He deals with more commercial rather than residential however he said the issue is that the board was not getting power. We did something very similar wiring It traditionally with the terminals and matching them to what we programmed on the thermostat. Heat works great and fine, AC doesn’t however. We had power to the transformer outside but not the board. I don’t believe we unplugged ABCD just took the wires out of them.
