ZEN21 Wiring: Totally Confused

My Zen21 arrived today and I expected to install it without any issues. When I started to remove the existing switches I soon got lost. I believe I need to follow the Zooz switches Option 2 as indicated on the instructions provided with this switch:

What is confusing me is the hook up for box 2. This box currently has 2 black and 1 red as shown above The iinstructions say I need to rewire this by removing 1 of the black wires completely (No idea what I do with it) and replacing the other with a neutral. Below are images of my current switches (first 3 images are in the Foyer, the other 2 are in the garage). Any help would be appreciated

I can’t see enough in the boxes to sort it out for you. However, an understanding of the how the switches work make help you sort it out. The two wires on the brass screws (one black one red) should be your travelers. They connect one switch to the other. Depending on the position of the switches power will travel down one or the other wire (on) or neither of the wires (off). The switches also have black wires attached to the black screw on each. One of these wires comes from power source (line). The other goes to the light (load). After the power passes through the light it returns to the power source via the white wire.

After you install the Zooz switches the red wire will not carry power from one switch to other any more. It will simply allow the Zooz switch to know if the regular switch is on or off. It is just a low voltage signal wire now.

The difference between the two options is where the load is connected. The upper diagram the load wire comes into the same box as the line wire. In this situation it is not necessary to pass power from box to box because both line and load are in these same box, thus the black wire between the boxes is unused and capped off. Since you don’t have a white wire on one of your switches I’m guess this is not what you have.

In the lower diagram the line (power source) comes in one box and the load is attached at the other box. Therefore the black wire is used to connect power from the Zooz switch to the load in the other box. The wire wire is used to return it. The wire wire is also attached to your regular 3 way switch so the Zooz switch can test the voltage on the red wire compared to it and determine its state.

Label your travelers and disconnect them. Then turn power on and use a meter or probe to determine which of the wires on the black screws is the power (line wire). Label that wire LINE. Label the other LOAD.

If you look closely at the diagram you can see they have colored some of the screws black to help you out on how to rewire.

Hope that helps you sort it out.

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I did get most of it straightened out thanks to Zooz Support and the wiring diagrams they sent. No problem getting it added to ST. The only problem I have is that I can not manually turn on/off the lights consistently using the Zooz switch. No problems with either the ST app or the secondary switch. When I say "consistently : I mean sometimes manually toggling Zooz swirch works fine but other times it does nothing. Can not find any pattern to when it works and when it does not. Almost like the switch is defective when using the paddle.

That’s definitely not normal. Hit up Zooz support again for that problem