Dimmer LZW31-SN with On/Off LZW30-SN in 3 way

I’m trying to use a dimmer switch (LZW31-SN) with an On/Off switch (LZW30-SN) in a 3 way. My line and load are in separate boxes with the load connected to the 2nd switch.

I want to put the dimmer switch in the line location (1st switch) and the On/Off in the load location. This is mainly because the line location is where we’d typically be dimming the lights from (it’s by the living room) while the load location is right beside the front door (so used for turning on/off the lights when arriving/leaving). Because I want to be able to dim, I don’t want to disable the relay of the dimmer switch. I’d much rather disable the relay of the On/Off switch.

Unfortunately, I can’t get this to work. I’ve tried various iterations and schematics (connecting the On/Off in a similar way as an dumb switch; connecting them in a similar way as an aux switch) but nothing seems to work (also, the schematic for 2 smart switches in the manual is for load/line in same box while they’re in different boxes in my case so not applicable). For some very weird reason, in every way I connect it, it appears the dimmer never sends currents through the traveler wire i.e. when I turn off the dimmer, the on/off switch has no power and the LED goes off. I believe that that’s the main issue here. I’ve tried (through both Hubitat and by using the config button) to change param 21 to “neutral” and param 22 to “3 way toggle” or “3 way momentary” but neither of those make any impact. I’m very lost as to how to ensure the on/off still receives currents when the dimmer is off.

I should also note that I did try flipping the locations (moving the On/Off to the line location and the dimmer to the load location). This worked fine (I disabled the relay on the On/Off to leave it always on and used association and buttons to control the dimmer via the On/Off). However, the switches end up being in the wrong location.


  1. Any suggestions on how to get my set up working?
  2. Can the smart switch connected to the line have the relay enabled while the relay of smart switch connected to the load is disabled?
  3. Does the dimmer still send current through the traveler cable when off? If it doesn’t, how does it work with dumb switches? Or is the issue that the current is enough to power dumb switches but not enough to power smart switches?
  4. What’s 3 way momentary? I assume that’s for aux switches but what exactly does the dimmer do in such an instance?
  5. What does param 21 do i.e. neutral vs non-neutral?
  6. Why doesn’t the on/off turn on at all when the dimmer is off? Doesn’t the neutral wire power the switch?


Tagging @EricM_Inovelli

So this is just my suggestion.

You need to be able to power both switches with uninterrupted 120V. Not a problem at the line side, but you’re going to have difficulty at the load box because it’s getting switched power.

What I’d recommend and this may not be to code, but I’d connect your traveler (red) wire to the same terminal as your line on the dimmer. That way power is just passing right along directly through that wire.

Then on the on/off switch, connect that traveler wire which now is a line, to the line connection. The black load wire that’s coming in would just get bypassed and you’d use a wire but to pass it on through to the light.

Once you associate the two switches, the on/off should be able to remotely turn on and off the dimmer.

Sorry, was going to reply about 2 hours ago and forgot. I actually did exactly what you suggested but connected the black wire instead of the red. Figured black could just mean hot and red could imply load so hopefully that brings it closer to code. I then disabled the relay on the on/off. It’s now working fine.

Thanks for your response!

Sweet! Yeah I thought that could maybe be closer to code as well after I sent that. Good thinking!