ZEN77 flickering problems resolved via parameter tweaks

Just bought a ZEN77 to evaluate for a new home I plan to convert to ZWave and EzloPlus.

I learned in the process, that Zooz went away from trailing edge dimmers and went back to Triac (leading edge) design. Strange choice I thought given the obvious benefits of trailing edge for low dim levels.

So I hooked the dimmer on a test bed and was surprised to see flickering light at full 100% level. If I was to get problems I more expected it at lower dim levels such as premature cut off or poor uneven dimming.

I have a video of this but this site doesn’t allow upload of it.

Anyone had similar problems?

Also my preference is something like the older Leviton Vizia dimmers. I have these currently but they are ancient leading edge Triac designs and not even ZWave plus. My ideal wish list in order of importance:

  1. ZWave Plus or higher
  2. Multi location (up to 4 or 5) dimming with companion switch, meaning you can set dim level at every switch not just the main one. All switches look similar and dimming is the same button press at each location.
  3. Trailing edge (MOSFET) switching technology
  4. Nice styling. While I liked the Vizia I never liked the tiny horizontal dimming bar, too tiny for my big hands.
  5. Available in white and ivory.

Anybody found a dimmer that gets checkmarks in these requirements?

Hello @curiousB

We found this matter in the Zooz support website Lights Flicker with My ZEN77 Dimmer Switch - Zooz Support Center

I had the same issue at home, but with a different device and the mentioned bypass solved it for me. (FIBARO Bypass 2 FGB-002 - The Smartest House)

Check it and let us know your comments, please.

Thanks for suggesting.

A circa 2024 dimmer shouldn’t need bolt on load shunts for LED bulbs. Maybe 5-10 years ago when this was all new but those sort of band-aide fixes are just not acceptable in 2024.

In my case it probably wouldn’t help because I also put a 60W incandescent bulb in parallel with the LED and the LED still flickers. The incandescent resistive current would be 10x the LED and swamp out any impedance related issues.

Maybe I just have a faulty dimmer. I have a query into Zooz.

p.s. the Fibaro bypass doesn’t seem to have UL or ETL safety certification. Since it is connected to the mains this is really needed.

Update: Zooz support has been pretty much useless. They are asking me what type of electronic element is in their dimmer (triac or mosfet). I would have thought they would know. When pressed on it they now claim both bulb and dimmer have “dimming” electronics made out of Triacs. Oy vey, These type of useless screening questions from level 1 support are frustrating and add no value.

I guess Zooz is off my candidate list for my new home. Too bad I liked the product offering mostly. I think they really made a mistake going backwards from MOSFET trailing edge dimming back to old fashion Triac leading edge dimming. They saved a few pennies but have a less robust design for electronic bulbs. Flawed strategy here.

Update 2: Through experiment learned that the light only flickers when dimmer setting is 99 or higher. So wrote a meshbot that if setting >98, set back to 95. This works but its kind of messy. If you double tap dimmer to 100% it flickers for 1-3 seconds until the meshbot kicks in and then drops to 95% and flickering stops. You don’t notice a dimming from 100 to 95% they both seem fully bright. I see there is a parameter 11 to set maximum brightness for the dimmer. Maybe I can set that for 98% and not need the clunky meshbot. On to my next experiment.

Update3: OK good news. By setting Multilevel maximum value to 97 (was 99, Zooz calls this parameter 11) the dimmer no longer flickers at full on. No need for a clean up meshbot to roll back the setting. So maybe this allows me to stay with Zooz. Not sure if they have a s/w bug that causes the flickering or is this some odd side effect of their circuit topology but I have a work around that might save the day. You also need to set Parameter 12 (Double Tap Behavior) to 2.

parameter 11 in Ezlo
parameter 12 ezlo zooz


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Check out the inovelli line of products, such as the red series 2-1 dimmer/switch: Inovelli - Red Series 2-1 Switch (Z-Wave) - 800 Series Long Range

One of the parameters you can set is if it uses leading or trailing edge dimming. Also, they ran into the same flickering issue with leading edge dimming that you are mentioning, and fixed it in their firmware. (at least on one of their other products, I’d assume this one as well though)