LZW31-SN, non-neutral, buzzing from light fixture

Hi all. I’m not sure where to file this one. It’s an issue that may involve everything: the LZW31-SN dimmer switch, the Aeotec Bypass, and the light fixture itself.

This project started with the light fixture. It’s a BUBO 12 Inch 20W Smart LED Ceiling Light. I quickly realized that my dumb switch (single pole, non-neutral) wasn’t going to be helpful anymore, so I replaced it with the LZW31-SN. I knew it required 25W, and the light fixture only pulls 20W, so I bought the Aeotec Bypass.

I put the switch in Smart Bulb Mode. I use Home Assistant; I set up automations for scene control. Frankly, it turned out even better than I imagined. It’s all great. I’m very impressed with this switch.

There’s just one problem: the light fixture now buzzes audibly.

It’s the addition of the bypass that causes it. On the dumb switch, no bypass, there was no buzz. Swap in the Inovelli switch, and it doesn’t function at all without the bypass; the light strobes and the switch is non-functional. Add the bypass and everything works. Except, the light fixture buzzes.

I’ve tried playing around with the switch settings. I thought, maybe if the light fixture received less than full power (even a tiny bit) it wouldn’t buzz. I turned off Smart Bulb Mode and pulled down the dimmer. That makes the situation worse. Anything less than full power makes the light fixture buzz even louder. And at a certain point, of course, the light fixture is getting too little power and shuts off completely.

Would the opposite achieve what I’m looking for? If I could give it 120% power, would it stop buzzing? There’s no way to do that, so all I can do is guess.

Is it this specific combination of devices that’s resulting in this? I’d like to keep the switch. Would a different light fixture not buzz?

Or are there some different switch settings I might try?

Thanks all!

Buzzing generally means that the bulb is not compatible with the dimmer. Unfortunately, if that is the case, it means the fixture isn’t going to work with a LZW31-SN.

I’d be curious to see if you experienced the same thing in a neutral configuration if there is somewhere you can swap it in for testing. But I’m still thinking it’s bulb compatibility, not neutral vs non-neutral.

This old house doesn’t have neutral wires, so unfortunately I can’t do any neutral wire testing.

The light fixture – which is a smart, WIFI unit – has no socket and no bulbs. It has a built-in panel of LED lights. So unfortunately I can’t swap out for a different bulb to do further testing. I’d have to replace the fixture.

If it comes to that, what sort of fixture should I be looking for? What’s wrong with this one that’s “right” in another fixture?

There is a bulb compatibility chart, which is being converted into an app or a better to read form. Not sure if the new version has been published. Here is the old one, but it is not too complete:

This one is better:

Ultimately, I’d look for a fixture that does NOT have built-in bulbs. Bulbs are easy to swap should what you pick not be compatible.

Yes sir, the second link you posted is the official bulb list :slight_smile:

@peterscene – This should take you directly to the app: Resources | Compatible Bulb & Fan List (App)

From there you can sort through the various options. Hopefully it helps!

Thanks for your help! I’ll look into alternate fixtures.