Okay, let's break down why your Zooz Zen21 isn't working with your existing 3-way wiring and what you need to do to fix it. The problem likely stems from the fact that the Zooz Zen21 needs a specific 3-way wiring configuration, and your old wiring is likely not compatible without modification.

Understanding the Problem Traditional 3-way Wiring

Older 3-way wiring often used one of the travelers (usually white) as a neutral for the second switch, or a constant hot. The traditional 3-way switch only needs to interrupt the hot wire and send voltage down one of the traveler wires depending on its position.

Smart Switch Requirements

Smart switches like the Zooz Zen21 always need a neutral wire at the switch location. The neutral is required to complete the circuit that powers the radio and other internal components. Furthermore, smart switches require a very specific wiring of the traveler wires from the companion switch.

Analyzing Your Description

You've indicated that you've run a neutral wire from the capped neutral in the box to your Zooz switch. That's a good start and essential, but the problem is still likely with the traveler wire configuration.

Assumptions Based on Your Description You have two 3-way switches. One switch is being replaced by the Zooz Zen21. The existing 3-way wiring worked with dumb (non-smart) paddle switches.

Common Problem Scenarios and Solutions

Here are the most likely issues and how to address them:1. Incorrect Traveler Wire Connections



Cause

The traveler wires from the existing wiring are not connected to the Zooz Zen21's traveler terminals in the way that Zooz expects. The Zooz requires a specific wiring, where one traveler is always connected to the load and one is connected to the line or neutral.

Solution

Consult the Zooz Zen21 documentation carefully. It has diagrams that show how to wire the 3-way switch with a dumb companion switch. Ensure that you understand which traveler wire should go to which terminal on the Zooz. It is essential to use the companion switch recommended by Zooz, otherwise you may not be able to dim from the companion switch.

Action

Find the model number for your companion switch, and compare it against the models recommended by Zooz.2.

Line and Load Reversed on the Zooz Switch



Cause

The Line (hot from the breaker) and Load (wire going to the light) wires may be connected to the wrong terminals on the Zooz switch.

Solution

Carefully identify the Line and Load wires. The Line wire is the one that's always hot (when the breaker is on). The Load wire is the one that goes to the light fixture. Connect them to the correct terminals on the Zooz.3.

Wrong Companion Switch Cause

Some smart switches are not compatible with standard dumb switches.

Solution

Replace your companion switch with the companion switch recommended by Zooz. Zooz has a compatibility checker on their website.

Steps to Take for Troubleshooting1. Double-Check the Wiring Diagram

Get the Zooz Zen21 manual (downloadable from the Zooz website). They have specific 3-way wiring diagrams. Print it out and refer to it closely. Post a clear picture of the Zooz wiring diagram here or send it to me.2.

Identify the Wires



Turn OFF the breaker! Safety first. Line Wire

Use a non-contact voltage tester to determine which wire is always hot when the breaker is on. This is your Line wire. Mark it clearly.

Load Wire

The wire that goes directly to the light fixture is your Load wire.

Neutral Wire

The white wire (typically).

Traveler Wires

The two remaining wires that run between the switches.3.

Document Your Existing Wiring

Before you change anything, take detailed pictures of the wiring at both switch locations (the Zooz switch location and the companion switch location). This is crucial in case you need to revert to the original setup. Label the wires in the pictures if possible.4.

Test the Neutral Wire

Use a multimeter to verify that the neutral wire is truly a neutral.5.

Wire According to the Zooz Diagram

Follow the Zooz 3-way wiring diagram precisely.6.

Test After Each Change

After making any wiring changes, turn the breaker back on and test if the switch works. If it doesn't, turn the breaker off again and re-check your wiring.

Important Considerations Safety First

Always turn off the breaker before working with electrical wiring. If you are not comfortable working with electricity, hire a qualified electrician.

Code Compliance

Ensure that all wiring conforms to local electrical codes.

Wire Gauge

Use appropriate wire gauge for the circuit (usually 14 AWG or 12 AWG).

Next Steps for You1. Provide the Zooz 3-way wiring diagram you're using. This is the most important piece of information for me to help you.2. Tell me the model number of your companion switch. This will help determine whether the companion switch is causing the problem.3. Describe the cable types entering the box where you are installing the Zooz. For instance, does one cable enter the box or two? Does the cable contain a black, white, red, and bare copper? This will help me determine the source of the Line and Load wires.With this information, I can provide more specific guidance. Flag for review