LZW31-SN completely unresponsive (via switch or app)

I have two of the new LZW31-SN Red Series Dimmer Switches. Both in neutral-wire single-pole installations, connected to SmartThings.

Over the last three days, one or the other or both of them suddenly become completely unresponsive. I’ll try to turn off the light, and nothing happens. Physical switch does not respond, trying to use SmartThings does not work, nada. Regular on/off button press does nothing, double/triple taps do nothing, holding up/down for dimming does nothing, favorite button does nothing. The only way to get it to respond again is to reset the associated breaker.

I have a number of other Inovelli switches around the house and no shortage of other Z-Wave repeaters, and these two switches are the only ones with problems. Wife Acceptance Factor on these is now zero, so I’ll probably put back the dumb switches that were there before unless there’s an easy solution here.

This is a bit of a long post and my setup is a tiny bit different, but I have noticed something similar in one of the two cases I mentioned: LZW31-SN with relay disabled spontaneously turns off with low loads.

In the case most similar to yours, I have two LED bulbs in a neutral-wire installation, but the LZW31-SN freaks out when the bulbs’ power draw gets below some magical threshold and “turns off” but also becomes completely unresponsive to local or Z-Wave commands to turn back on. It does not seem to happen when the bulbs are at full power. My added complication that these are smart bulbs and so the actual power of the load can vary depending on their configuration, but with the neutral wire, I assume this shouldn’t matter.

Are you sure that pulling the air gap at the bottom of the dimmer doesn’t work? That works for me and should be more or less the same from the switch’s perspective.

I still don’t know what’s going on, but if a load that draws more current works around your problem, I suspect it’s similar to mine.

There is also this thread: LZW31-SN turns off randomly as well as this related questionnaire: Dimmer Switches | Random Shut-off Issue | Data Collection Thread. However, it’s not clear to me whether those people mean literally just turning off or the switch basically crashing and not only turning off but also becoming completely unresponsive unless power to the switch is pulled and restored.

I saw those “turns off” posts, but it definitely sounded more like the switch was randomly toggling to the off status for its load, not that the entire switch was just crashing.

It feels particularly weird that even just up/down on/off taps don’t work. I’d have hoped that functionality would work even if any advanced functions crashed.

I’ll try the air gap thing tonight - apparently I don’t know how that works. I thought it was a button that could be pushed, but it sounds like it needs to be pulled outward?

Yep, the air gap just pulls out, sometimes with great difficulty, and it (as far as I can tell) completely cuts power to both the load and all aspects of the switch (radio/circuitry). On some older GE ones I think it only cut power to the load, but those are the only ones I’ve heard of where that happens.

And I agree, their problems sound like the load just toggling to off, whereas I think we’re experiencing some sort of failure that renders the switch unusuable until it’s power cycled, though it also happens to turn the load off (at least in my case).

I may have missed this, but what type of bulb is used on these dimmers? Have you tried to exclude,factory reset, include? I had to factory reset mine.

The air gap does seem to work, so that’s good to know for next time it happens.

One of the two switches I have is controlling a light fixture with three 60W equivalent Philips LED dimmer bulbs. The other is controlling a fixture with five IKEA dimmable LEDs. I don’t recall the exact type/model for either one.

There is also this thread: Switch completely frozen

Which I think is the same as what you are experiencing. And I’m also worried about how long I can keep my wife from noticing and making me put back in the dumb switch! :slight_smile:

I have the older gen 1 dimmer and am also experiencing the same thing, so seems to not be specific to Gen 1 or Gen 2.


Are the dimmers grounded? It’s strange that it’s happening on two different circuits with different generation switches. Maybe a voltage surge or leak somewhere? Maybe even a wonky GFCI on the same circuit?

I had a similar issue at first but turned out I wasn’t using the right device handler. Changing to the correct one fixed my issues.

Im having the same issue with one of my switches. What are you guys talking about when you say the air gap works?

There’s a little piece of plastic at the bottom of the switch that you can pull forward (out towards you away from the wall) which cuts power to the switch. When you push it back in, the switch resets and usually works again.

Unfortunately it doesn’t solve the problem permanently. My switch gets stuck like this at least once a week which is annoying – enough that I’ve only kept the one in my own bathroom, as my wife would NOT put up with a simple light switch that stops working once a week.

I’m echoing the concerns here and have a very similar issue. I’ll repost what I mentioned on @BertABCD1234 's thread above:

Just checking back in a few months later to note that this issue never resolved itself – the switch goes dead at least once a day and will be getting swapped out soon for a GE Switch. A light switch that can’t switch the light can’t stay any longer.

@thenrich - Have you tried updating to the latest firmwarr?

I haven’t – looks like that’s more complicated than just going into the device settings in smartthings, if these are the right instructions: https://support.inovelli.com/portal/kb/articles/how-to-s-general-how-to-update-firmware-z-stick-z-wave-pc-controller

Not super interested in buying a $35 zwave stick to fix a $30 lightswitch.

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Correct, those are the correct instructions. It’s another expense, but until SmartThings allows/programs OTA updates, it’s a necessary…Fortunately, for us Hubitat users, there is an alternative other than buying a Z Wave USB.

I found one of the sticks on eBay for cheaper, so I’ll give that a try, but it’s super frustrating that this is even necessary. It’s a light switch. I get that the “smart” functions are subject to lots of complicated software interactions, but on/off by itself should not ever fail.

I don’t know if anyone has followed those firmware update instructions lately but they are not as foolproof/easy as advertised. The software required is not intuitive to find (the provided link is not current), the interface is different, and the OTA update never went through. “Should take 5-10 minutes” – I gave up after it was processing for 30.

So… unfortunately I think I’m still going to have to swap the switch out for something else. :-/

Shoot me a PM, let’s see if swapping out the switch will fix your issue. I’ll flash the new firmware on the one we send out to you. Apologies for the issues, we’re trying to figure this out as well.

@thenrich -How far away from the hub is the light switch? I flashed two dinners in a mere 5 mins total, but I moved the Z stick right next to it.