Blue Series 2-1 buzzing in dimmer mode in a spot where a Red Series dimmer did not (edit: ... as much)

Hi all - the support team suggested I post this here to get your input.

I replaced a Red Series LZW-31SN with a new Blue VZM31-SN. The Blue Series buzzes, especially when acting as a dimmer, in a location where the Red Series did not.

It is single-pole with 3 LED recessed-style bulbs (9W each). These are the bulbs [1]/[2].

Is there anything I can do to troubleshoot this? Or is the switch potentially a dud?

I first noticed the buzzing after switching the switch to dimmer mode. It is louder when dimmed to mid-point levels, and noticeable from about 2-3 feet away. (You can notice it when you walk by.) After, I switched it back to on/off mode, and noticed it buzzes in that mode too but only slightly – noticeable from about 6 inches away.

This may be unrelated, but there were a couple of other odd points about this switch that gave me pause:

  1. It did not enter pairing mode on initial power up (no blue pulse). A factory reset (config + up for 20 secs until red) did not trigger pairing. 3x tap of config button did not trigger pairing. Finally, I was able to pair it successfully by pulling the air gap; and after pushing it back in, pairing mode was triggered.

  2. The air gap was rather hard to pull out: I had to use a coin, could not use my finger.

For reference my hub is Home Assistant + ZHA.


Have you swapped in another blue to see if it is a hardware issue?

I was able to try that out today. The second Blue I swapped in buzzed the same way.

Then I swapped my original Red back in. It turns out it buzzes a bit too - but only half as loud. You have to have your ear a foot away to notice, which I guess is why I hadn’t before.

Not sure where to take this from here. Would this indicate a problem with my lights? They are very common Home Depot ones.

It could be one of the lights. Some wafer lights have traditionally problematic with Inovelli’s.

Since the wafer lights are easy to temporarily remove, I’d be curious to see if you removed those 2 temporarily to see if it still buzzes with just the light fixture.

Then do the opposite, depending on how easy it is to take the fixture out of the equation.

Curious to see if the dimmer works with one type, both types but maybe not both types together.

Ah - I should clarify. The Energy Star website I linked to is confusing because it has a photo of an unrelated light fixture on it (under “Find and Compare”).

All 3 of the lights are the same type: the Commercial Electric 5/6 in. Color Temperature Selectable Integrated LED Recessed Trim model, just an older version of the one now available on the Home Depot website.

I had one instance of a red series making a noticeable buzzing sound. It was in a non-neutral configuration. I added a neutral to the box instead of installing the relay, and it’s been happily sitting there for around 2 years without making a sound.

By any chance is this switch in a non-neutral configuration?

Thanks for the tip, but this is with a neutral wire.

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@kreene1987 and I think @stu1811 (maybe) had wafer retrofits working with a Red dimmer. One of them may have swapped out for a Blue. If they did, they can comment on how well the Blue works with their wafers.

I wish. We only have switched outlets in our bedrooms.

Another data point on this-
I have a Blue set up as a dimmer, neutral single-gang. Load is 6 Feit PAR16 floods, 4.1W each, dimmable. With a Zooz Zen27, the dimming was silent. I can hear a faint buzz coming from the lights with the Blue doing the dimming. Only at 100% does the buzz go away.

You got an attic? We’ll put some lights in!

Full of snow insulation