Blue Series Dimmer Switch (VZM31-SN) is flickering - what to do about it?

[tobythetenor]

Lights attached to my Blue Dimmer switch (VZM31-SN) flicker periodically, approximately every 10-15 seconds.
The switch is installed in single-pole mode WITH neutral wire installed.

The load are Cooper Halo HLBC6 downlights, which experience no flickering with other dimmers, including Leviton Sureslide (analog), Lutron Maestro (digital) and Jasco Enbrighten (Zigbee), which I have tried on them.

The flicker does not occur with an incandescent bulb (I used a 40W oven bulb to test, which is similar to the ~40W the Halos draw), but it is reproducible with some off-the-shelf LED bulbs.

I have tried a dimmer bypass (in addition to the neutral wire). This does not stop the flickering, but changes its characteristic a bit (without it’s more of a noticeable drop in brightness, whereas with it, the lights actually turn fully off, if only briefly).

The problem I’m experiencing sounds very similar to Red Series Dimmer flickering intermittently - Switches / General Discussion - Inovelli Community, which suggests disabling power reporting.
I tried disabling power reporting by setting Endpoint ID 0xfc31 → active energy report 0x0014 and active power report 0x0012 to 0.
Unfortunately, this wasn’t effective - I still see power reports and the flickering continues.

The flicker is only noticeable at medium settings between about 15% - 90% brightness, not at 100% or at very low levels.
You can actually see the flicker in the power graph - what should be a smooth line is jittery:

One more thing I tried is using the single-pole full-sine mode, which unfortunately also does not address the flickering.
The firmware is 2.18.

I have already contacted Inovelli support, but there is no conclusion so far.
Would anybody have any additional tips I could try to resolve this?

[rohan]

Have you tried trailing edge dimming mode?

[tobythetenor]

Yes. When I try to set trailing edge dimming mode I get error Failed to perform the action select/select_option. Failed to write attribute eading_or_trailing_edge=<InovelliDimmingMode.TrailingEdge: 1>: <Status.INVALID_DATA_TYPE: 141>
Having looked into this further, I am under the impression that trailing edge mode only applies to three-way installations, not single-pole.

[rohan]

Trailing Edge is only available on neutral single-pole and neutral multi-way with an aux/add-on switch (multi-way with a dumb/existing switch and non-neutral setups are not supported and will default back to Leading Edge).

I believe most (all) of the hubs are configured to treat that parameter as read-only. You can set it from the switch by holding the down button and tapping the config button 13 times. You should see the switch bar turn teal if it works.

[tobythetenor]

Aha!
Am going to try this over the weekend (am out of town at the moment).
Many thanks for the tip!

[tobythetenor]

Unfortunately, switching to Trailing Edge mode does not resolve the flickering issue.
The above procedure worked, and the dimmer now shows configured with Trailing Edge mode in HA. I definitely see a difference in that the dimming curve itself is smoother now (less choppy), but once the dimming level is reached, the flickering continues.
I tried both in regular- and full sine mode.
I also recorded a video, but the forum tells me that new users cannot upload videos.

Meanwhile, I found a forum entry from January 24 that describes my issue exactly:

Lights flickering at low dim level with Blue 2-1

Hello, Has there been any real investigation into this issue by the Inovelli team? It seems to be a fairly common problem with several threads across both new Blue and Red dimmers reporting the same issue, with all of them reporting other smart switches by different manufacturers do not experience the same issue with the same bulbs. I think the reported power usage graph reporting above is pretty telling of the issue. I have been experiencing the issue with all of my switches/bulbs since inst…

Since my lights are built-in, I don’t have the option to switch bulbs like the OP of the other post.
From this post and the various red series posts I found, it seems this is a hardware issue that cannot be resolved through firmware or configuration.
I’m happy to try any other suggestions though.

[grooves12]

I’m still troubleshooting this and have been in contact with @EricM_Inovelli and @Eric_Inovelli through the beta channels trying to find a fix.

Here is everything I tried above with no improvement:

• Leading Edge/Trailing edge
• Several different types and manufacturers of bulbs (mostly can light retrofits)
• Disabling all power reporting parameters
• Factory resets of switches

What does work perfectly:

• Zoon Zen77
• Leviton Zwave LR800 Dimmer

Finally I tried something that might have solved it. I noticed that multiple lights will operate steadily for some time (a couple of minutes) and then have a quick few seconds of flickering/pulsing. I also noticed that often, but not always, several lights will flicker at about the same time, but not in perfect sync or length, which to me indicated that it wasn’t a power issue at the panel/circuit level. If that were true, they would all flicker at exactly the same time/frequency, which wasn’t happening. So what else, could several lights do at the same time that might be causing the issue? Send/Receive packets across the Zigbee network.

To test that hypothesis, I unpaired the lights from my hub, so they shouldn’t be sending/receiving packets, and lo and behold I have no longer seen any flickering. I haven’t been watching it like a hawk, but it’s been about 12 hours and I haven’t seen any flickering yet. I’ll give it another night to see if I notice anything. I will then re-pair the switch to see if the flickering comes back. If it flickers when paired and doesn’t when unpaired, that points to the switch being unable to maintain the proper voltage when it is receiving/transmitting data packets.

@tobythetenor Can you try unpairing your switch and see if the flickering is improved/resolved?

[grooves12]

Update: I confirmed that there was no flickering for several hours. So, decided to pair the switch back to the hub. Almost immediately upon getting the message from the hub that said “device found” the lights began flickering again and reverted back to the previous behavior.

[tobythetenor]

@grooves12 many thanks for the tip!
Indeed removing the switch from HA seems to stop the flickering, at least in the few hours I’ve been able to observe it so far.

I also noticed that the dimming curve is completely smooth now, while when connected to HA going from one brightness level to another was always a bit choppy - it’s almost as if there is some kind of feedback loop where the dimmer sends the new level back to HA but then also reads the desired level from HA at the same time.

I’m connecting via a Sonoff Dongle Plus-E with firmware 7.4.4, and am using Home Assistant with ZHA integration for this switch.

Sounds like perhaps this can be fixed in firmware after all - am looking forward to developments in the thread.

[jordidaz]

I am running into the same issue and have noticed it flickers more often when changing parameters from HA - so the theory seems to make sense. This has been going on for over a year now and I hope this can be fixed via firmware - it’s really annoying

[grooves12]

I see a quick voltage drop to 0 that is correlated with the flickers, which only happens when connected to the Zigbee network. When the device is unpaired, no voltage drops and no flickers.

[rdb]

Glad to see this thread. Have been observing the same thing… random flickering at any dim level. I’ve been searching for a disc LED downlight that doesn’t exhibit the behavior, but haven’t found one yet. Anxious to see where this goes; I’ve got a house full of Inovelli Blue’s.

Good detective work, @grooves12.

[Phillystax]

I just installed my Blue dimmer switch as well (firmware 2.18) and I’m seeing the flicker too. Power will usually bump up and down 0.1W and sometimes as much as 1W which is what’s most perceptible. Hoping for a firmware fix soon. This was my initial tester purchase to see if I should buy more throughout the house. Right now I’m pausing until this is resolved. I do love the fact that this switch can be On/Off, Dimmer, or Smart Bulb controller.

[jordidaz]

@EricM_Inovelli just wanted to have this on your radar given how impactful this is for the affected customers. Thanks!

[rohan]

Eric shared an update in a different thread. Crosslinking it here Lights flickering at low dim level with Blue 2-1 - #32 by Eric_Inovelli

[mark_westcott]

Just installed this switch yesterday. Seems great, except I’m having this exact issue, which is a non-starter for me. It replaced a cheap TUYA dimmer that didn’t have this issue, only couldn’t dim as low as I wanted, so bought this due to the communities recommends. Is there a fix yet?