Looking for a sanity check on an 3-way light circuit that I'm switching out smart switches.
Here's the scenario:
1. Box A is a single gang box that has a 14-3 wire and a 14-2 wire in it. It appears the 14-2 wire here goes to the light fixture in this circuit. The 14-3 wire goes to Box B.
2. Box B is a double gang box that has the 14-3 wire in it, along with 2 other 14-2 wires. It appears that power enters into this box on one of the 14-2 wires and then power exits to an secondary(unrelated) ceiling light via the other 14-2. The outgoing/old 3-way switch in this box had a black wire connected to the black screw and it was pigtailed with the other blacks in the box. The red and black wires from the 14-3 were connected to the brass screws.
I've put the PICO on Box B side, so I took all three wires connected to the original outgoing switch and connected them in a wire nut.
Moving back to Box A, I hooked things up as per Lutron's instructions -- they suggest to identify the common (the wire attached the black screw on the old switch) and connect it to the black wire on the new dimmer. And then take the others (the red and black wire from the 14-3) and connect it with the red wire on the new dimmer.
Did that, and lights didn't work. In the original config, the wire connected to the black screw in Box A was connected to the black wire that looks like it's headed to the light fixture.
I then swapped the wires around in the Single gang box (Box A) -- I connected the black wire on the Lutron dimmer with both the red and black from the 14-3 (from Box B) and connected the red wire on the new dimmer with the black wire that looked to be headed to the fixture. Low and behold, this works.
So I'm just curious if i'm missing something -- this isn't what Lutron shows in their diagram (unless I'm looking at the wrong one?)
I want to make sure this sounds correct before I close everything back up.