Home>Discussions>ELECTRICAL & LIGHTING>adding the third LED out of four caused the dimmer to stop working?
7 posts / 0 new
Last post
bkohl
adding the third LED out of four caused the dimmer to stop working?

We've been trying out LED bulbs around different places in the house. Two Home Depot dimmable PAR30s worked great in a four-light-bulb fixture in the kitchen. I added a dimmable Philips BR30 bulb, and suddenly the dimmer doesn't work (on any of the LEDs - it works fine on the one remaining incandescent flood), and the two PAR30s dim suddenly, one at a time, without warning or anyone touching the light switch.

I don't have another dimmable fixture that I could try out the Philips to see if it's a dud. The bulb gives out light, in this fixture and in another.

What do you think my next trouble-shooting step should be?

thanks!

Re: adding the third LED out of four caused the dimmer to stop working?

You might try removing the last lamp to get back to an acceptable state. I wonder if one can mix manufacturers? They may have different trigger points.

Good Luck from Columbiana, Alabama
Maurice Turgeon, http://thesemi-retiredelectrician.com

bkohl
Re: adding the third LED out of four caused the dimmer to stop working?

I took the Philips out. Oddly enough, that didn't totally fix the problem. All three LEDs apparently don't work at the lowest dim setting - I think I never really noticed because the other incandescent bulbs in the fixture were hiding the effect.

I took all the bulbs out of the fixture and then rotated all three LED bulbs into one socket, one at a time.

Both Home Depot bulbs both try to dim, stay dim for a few seconds, and then return to almost-full-strength. And then flicker back to dim every once in a while.

The Philips bulb, if I turn the light switch on at any dim setting other than full strenth, becomes a strobe light. Very disconcerting :) If I turn on at full strength and then dim, nothing happens -no dimming.

I don't know what kind of dimmer is installed - it was here before I was.

dj1
Re: adding the third LED out of four caused the dimmer to stop working?

We discussed this subject previously. If your dimmer worked fine with the old fashion incandescent bulbs but doesn't work properly with LEDs, then use incandescent bulbs.

LEDs are nice and bright, but they don't always work well with dimmers.

canuk
Re: adding the third LED out of four caused the dimmer to stop working?

Dollars to donuts it's a compatibility issue between the dimmer and the LED bulbs.
The dimmer is a standard incandescent dimmer which works fine for what it was designed to be used for --- simple resistive element load of incandescent lamps.

However , with LED/CFL lamps they have finiky electronic circuitry that produces a reactive load to the dimmer. The electronics of those LED/CFL lamps are sensitive to the way the standard incandescant dimmer outputs the manipilated duty cycle to the lamp --- incandescant lamps aren't as sensitive which is why they work fine.
Quality of the dimmer is also a factor. Cheap quality dimmers can have more hysterisis reaction to line and load along with more radio interference --- which also plays havoc with LED/CFL lamps --- than a high quailty dimmer.

To add , different manufacturers lamps will react differently because of design and component differences.

There are manufacturers of lighting controls that are making dimmers specifically for LED/CFL lamps.

Example .....
http://www.lutron.com/Education-Training/LCE/Pages/DimmingCFLsandLEDs.aspx

bkohl
Re: adding the third LED out of four caused the dimmer to stop working?

After some thought, we just ended up taking out the dimmer. These are overhead lights in a tiny, windowless kitchen - I've never wanted to *dim* them. There was a dimmer in the hardware store made for LED bulbs, but we just bought a regular switch for $1.70 and replaced it ourselves. We're saving about $1.70/month in electricity from the new bulbs, so that seems fortuitous.

Re: adding the third LED out of four caused the dimmer to stop working?

The LED dimmer switches are engineered for LED dimmable light bulbs. A regular dimming light switch can dim a dimmable LED bulb but, there may be problems like a non LED dimmer switch can’t dim the LED bulb low enough, Drop outs, Humming noise. You need to buy LED dimmer switches.

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.