Red Series Dimmer Switch Buzzing (LZW31-SN)

I just installed a new Red Series Dimmer Switch (LZW31-SN) and I like the functionality so far. However, there is a loud, audible buzzing noise I can hear coming from the switch. It’s quite noticeable from a distance and the I don’t have the same issue with my Red On/Off Switch (LZW30-SN) which are powering the same type of bulbs or my older NZW30 switch.

Is it possible that there is something wrong with the hardware? The date code is 0919, if that is relevant at all. On another note, I notice that the dimming transition isn’t smooth even when the ramp rate is set to a long time (8 seconds).


Welcome to the the forum…

I’ve not experienced this although I’ve read similar complaints from others. In any situation where the issue may be caused by a incompatibility with a specific LED bulb, I try to install an incandescent bulb and see if the issue goes away. This isn’t a solution but it tells you if the dimmer can work with a different bulb or if it is truly defective.

Thanks for the suggestion. The problem would be finding an incandescent bulb still around the house somewhere to verify. My dimmer switch is installed with the neutral wire and the total load is reading at ~60 watts for all of the lights, which are Sylvania Smart+ RGBW RT5/6 bulbs.

Ah Ha,

Do you have the internal relay disabled? If not that is likely the problem. The Red has an internal dimmer (obvious) also the Sylvania Smart+ RGBW has an internal dimmer. You can’t have a dimmer powering a dimmer. From what I understand the internal relay bypassed the Red dimmer, however I’m not too familiar with the internal relay to say in detail how it functions.

I just tried tapping on the config 8x to turn off the internal relay. There is still the same audible buzz. Now I’ll have to use the Smartthings app to turn on/off the switch and must rely on scenes turn the lights on or off, correct?

I want to avoid this because I’ve tried this with my Red On/Off switch and the delay is far too long just to simply turn the lights on or off. Also, with the internal relay off, I can’t use the physical switch for dimming unless I use some type of mirroring, right?

This suddenly got more complex than I was expecting. I appreciate the help though!

There are a variety of reasons for the buzz but as a data point I did just RMA a dimmer for buzzing. A second dimmer in the same location did not buzz.


Any thoughts on how to fix this issue? Thanks.

1 Like

I’m having a similar buzz on 2 red dimmers.

1 has an incandescent chandelier and an LED which buzzes ever so silently while off but audibly when on.

The newest red dimmer has 1 led 23W dimmable fixture but it constantly buzzes while the light is on or off, and the light turns on strange. It comes on, flashes off then dims back on until it reaches it set point.
Wiring seems fine.

I have one other red dimmer that doesn’t hum at all.

Edit: did more research and it seems like the led fixture is triac and not mosfet.

Same problem. Just installed one today, and have buzz from both the red series dimmer and LED bulbs. (10) 16w fluorescent (Toggled brand) daisy chained together.

Is it a CFL or one of the tube florescent? Must florescent bulbs are not dimmable.

Toggled makes both dimmable and non-dimmable tubes. The dimmable ones are the D series. Posting your model number would help.

Also, these are direct-wire i.e no ballast. So if you put these in an older fixture did you remove the ballast/re-wire?

Correct, I removed the Ballast, rewired with replacement ends provided with Toggled (Model :D416-40321-2 rev 002). Noted it says dimmable right on the box. Also sent a note to Toggled support (Troy, MI company, BTW) to ask which switches work with your lights.

EDIT: Noted here are the switches that I can use:, and the only smart switch listed is a $120 Lutron PD-5NE. @Eric_Inovelli, MI company, any chance? :slight_smile:

When they are used with transformers, the red series is only compatible with MLV, not ELV. Since the switches specified in the link you posted are ELV dimmers, and the spec sheet says that those dimmers work best, that makes me suspect that the red dimmer is not going to be compatible, hence the buzzing.

1 Like

Correct, from Toggled support: ‘Toggled tubes work best with ELV/reverse-phase dimmers.’