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I have three flood lights (of this model) controlled by a single switch (this one).

When turned on, the lights seem ok for a few minutes, but then they start to slowly blink on and off. Each blink lasts between 10 - 30 seconds. So, a light will be on for 10 seconds, off for 20 seconds, on for 15 seconds, off again for 30 seconds, etc.

The length of time between blinks is variable and the lights are not in sync with each other. The effect is like a slow-motion disco.

The lights were previously on a dimmer. It was suggested to me that the dimmer switch might be at fault, so I replaced it with a normal switch. The problem has not gone away. When I had the dimmer, I could set the dimmer at half power and the problem would not occur (though I would be stuck with constant mood lighting).

I had an electrician come out, inspect the problem, and give up. He suspected heat-related issues, but he checked the temperature and said it seemed ok.

Edit:

Based on suggestions in the comments, I have replaced one of the CFLs with a 12 watt LEDs (this kind).

Unlike the CFL bulbs, the LED bulb has a noticeable flickering when it is on. In addition, it also still exhibits the "blinking" effect described above. In other words, the problem persists.

I could replace the other two CFL bulbs, if somebody thinks that one of the other bulbs may be causing issues with its siblings. I don't know what I am doing, but this seems unlikely to me, so I have started with replacing only a single bulb.

Would using incandescent bulbs make a difference?

  • After replacing the dimmer did you also replace the bulbs? – ben rudgers Aug 10 '14 at 23:30
  • No, I did not. I will give that a try tomorrow. – Chris Nielsen Aug 11 '14 at 0:38
  • I would agree with the electrician, it sounds like heat issue. The CFL doesn't produce enough heat to trip the heat sensor in the can, but it could have a faulty sensor in the bulb. Try purchasing a new bulb from a different brand. – diceless Aug 11 '14 at 4:44
  • I have updated the question with the results of replacing a bulb. – Chris Nielsen Aug 11 '14 at 16:40
  • Did these can's always have the have the flicker issue? Since they are blinking at different rates, it doesn't sound like an electrical connection issue. But having a thermal switch problem in all three cans seems odd as well. You can try using Incandescent. But if that has issues you might be left with having to replace the cans. – diceless Aug 11 '14 at 20:00
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This very much sounds like a thermal trip issue in the fixtures. If the lights are not blinking in sync with each other then this not a power supply circuit problem. And you've tried different bulbs. It is a fixture problem.

  • I just got around to replacing one of the fixtures yesterday. This did indeed solve the problem for that fixture, so I will be replacing the other two next weekend. Thanks! – Chris Nielsen Sep 2 '14 at 13:37

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