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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.