@LN- oh. And I'm happy to link to a vimeo, if that would be helpful.

@LN- 

There are known possible causes for the connected bulbs to flicker or buzz.

-Wiring, like you mentioned, this is the most common cause. To see if it is the outlet, you can try wiring the HS220 to another outlet to see if the issue follows the switch or not.

-Confirm that the bulbs are wired in parallel.

-The outlet that is being used is needs to be operating at 120V with 60Hz frequency, a different frequency (50Hz) may cause flicker.

-Make sure the bulbs being used are dimmable or incandesent bulbs. There is no compatibility problem with incandesent bulbs, but the wattage needs to be made aware so not to go above the max (300W Incandescent, 150W dimmable LED). 

-Various brands used in together can cause a issue leading to flicker or buzz.

interesting problem. i have several hs220 dimeers around the house. one has 2 5watt lceiling bulbs another has 4 5 watt ceiling lights and a thrird that has 8 ceiling lights, all in parallel. in the 8 light switch/dimmer i can control pn/off but no DIM. the dimmer rports simming, by the led array on the switch (dots on top)   also the app reports success. i tried several hs220's all the same. Does anyone know if there is a limit on the bulbs?? Again I can on/off the switch fine and although the dimmer reports proper success the 8 lights ae either on FULL or OFF   example  turn on at 20%  ; turns on ful   once on   trying to reduct to 20% has no effect    but app reports success  any thoughts

BTW added not e this circuit ( 8 bulbs) were on a manual dimmer prior and worked fine

Tony wrote

 

-Make sure the bulbs being used are dimmable . . . .

 

@Tony 

I'm actually using five Philips Hue White and Color Ambiance BR30 (120v, 9 watts).  These are dimmable bulbs.  They properly dim when wired to a regular switch and associated with Alexa.  (Again, I wanted to use the HS220 because Alexa randomly turns them on, which is no good when we're out of town.  I was willing to give up the bulbs' color feature, but we need them to dim.)

When I "deregistered" the five bulbs from Alexa, wired them to the HS220, and set up the switch with the Kasa app, the bulbs would not dim.  When dimmed on the Kasa app (or by voice w Alexa), they just blink rapidly.

I'm returning the switch.  I have a switch from an "L" brand that dims smart bulbs fine.  I'll either try that, or just turn off the wall switch when we go out of town.

So, bottom line for me: The HS220 does not work with Phillip Hue Ambiance BR30 dimmable bulbs.

-L!!

@LN- Hi

The Phillip Hue BR30 is a smart bulb.

You should not dim a smart(electronic) bulb, it will fail or work erratically.

@B.Will 

Thanks, B.

Yes, this is a smart bulb.

The spec from the bulb manufacturer -- Phillips -- specifically states that the bulb is "Dimmable via smart device only[,]" so I'm not sure why you indicate that you should not dim this bulb.  And, yes, this is an electronic bulb.

The bulb's dimming functions work fine with Alexa (wired to a regular, non-smart switch) and with the Leviton DW1KD-1BZ smart switch.  The bulbs will not dim when wired to the HS220.  Thus, the HS220 is not suitable for my application, i.e., dimming my kitchen bulbs.

Rgds,

-L