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Why are my LED cans flickering?

Posted by amandasplit (My Page) on
Mon, Feb 18, 13 at 0:36

We just installed ten DMF LED cans in the kitchen and they hum and flicker when dimmed and the dimming range is not that great. My husband adjusted the dimmer switch (Lutron CL) and that helped but also lowered the dimming range. Did we get duped on this brand (husband got sold on them for their high lumen output and Cree chip)? Is there anything that might be causing this that we aren't thinking of? Should I just retrofit it for the Edison base spend the money on Ecosmarts at HD?

For what it's worth, when not dimmed the lights look great.


Follow-Up Postings:

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RE: Why are my LED cans flickering?

I'd contact DMF and Lutron. Dimming LEDs is a little more complicated than ordinary incandescent lamps.


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RE: Why are my LED cans flickering?

Dimmers turn the power on and off rapidly, 120 times per second. The LEDs respond faster than do incandescent lamps and the OFF part of the dimmer operation is more noticeable. Mine flicker when dimmed drastically. It is the nature of the beast. Ditch the dimmer if it is intolerable.


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RE: Why are my LED cans flickering?

To take the mystery out of dimming LEDs Lutron has developed a testing lab. Lighting manufacturers send their product to Lutron to see how it performs with various Lutron dimmers. This is one of the best ways to know in advance how products are going to perform but one has to read carefully and be able to understand the report. Is difficult to keep the reports current as new LEDs are released and older ones updated often. You should not assume that an updated product which previously received a good report will be the same.

Here is a link that might be useful: Lutron LED report card


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RE: Why are my LED cans flickering?

The LEDs are running on the output of an AC to DC power supply to produce the low DC voltage the discrete LEDs use.

The power supply design sounds like it is (at least) not compatible with the type of dimer you have chosen, and may not be compatible with ANY dimmer.

Ask the LED manufacturer what dimmer THEY recommend.


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RE: Why are my LED cans flickering?

If you are using an old dimmer, replace it with a new one that is meant to be used with LEDs. We changed out some recessed cans to LEDS recently and noticed that some of the ones on dimmers flickered. We replaced the dimmers and lost the flicker. Easy trip to Home Depot or Lowe's.


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RE: Why are my LED cans flickering?

Thanks for all the feedback! We are using a new Lutron CL dimmer for LED. We were able to adjust it to make the flickering stop, but now it hardly dims. We called DMF, waiting to hear what they say.

I blame title24 for this! If we didn't have that we would've used the Eco smarts.


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RE: Why are my LED cans flickering?

amanda, I don't understand your title 24 and Ecosmart issue (other that perhaps $$). Ecosmart's versions of the CR6 and CR4 come in GU24 socket versions, which will pass T24 last I checked.


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RE: Why are my LED cans flickering?

Oh yeah. You're right. We just had trouble finding gu24 cans that were definitely compatible. We found one that we thought might work (Elco) but we couldn't be sure they would fit the ecosmarts and didn't want to deal with buying and returning. And actually the lighting store we were working with does not accept returns. Also at the time no one had the gu24 Eco smarts in stock in 4". We are seriously thinking of doing the pigtail thing someone suggested to us before and turning our DMF cans into Edison sockets. Or just living with basically non dimmers.


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RE: Why are my LED cans flickering?

We replaced some 4" with EcoSmarts kits from Home Depot. They were more expensive and they had fewer in stock than the 6", but we were able to find them. We replaced hot halogen bulbs adn even with 10 ft ceilings, I can tell the difference in the room.


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RE: Why are my LED cans flickering?

I'm not too experienced with LED lights yet, but if they're anything like compact flourescents, not only do you need a dimmer specifically for LED bulbs, you may also need to get bulbs that are dimmable.


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RE: Why are my LED cans flickering?

I thought I'd follow up in case anyone ever has a similar issue. We called DMF and they gave us an approved list of dimmers and oddly enough the Lutron dimmer listed is the one for incandescent bulbs, not CL. So we switched it and that helped a teeeeeeeeeny bit. Still not great. We should've gone with the Cree!

Thanks everyone for all your help.


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RE: Why are my LED cans flickering?

"We called DMF and they gave us an approved list of dimmers and oddly enough the Lutron dimmer listed is the one for incandescent bulbs, not CL. So we switched it and that helped a teeeeeeeeeny bit. Still not great. We should've gone with the Cree! "

The power supply design to work with ANY type of dimming is more expensive to design and manufacture.
It takes extra circuitry and parts to convert the width of the AC wave into a dimming control signal, while still tolerating the distorted voltage and current available from the dimmers

The 'magnetic' dimmers use a different device to control the AC waveform, but the power supply (CFL, florescent ballasts, LV, LED) needs to be specially designed for one type of dimmer or the other.


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