Temperamental Mercury Vapor Light


Old 10-30-02, 05:37 PM
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Temperamental Mercury Vapor Light

In July we installed a dusk-to-dawn mercury vapor light (100w) on the outside of our home, high up in a roof peak. It works great but, well, erratically.

It will be on several nights, then suddenly not come on at all. And not on the next. And then back on for one or several nights. We haven't figured out any rhyme or reason as to when it lights up. The level of other lighting in our area is pretty much the same from day to day (= none, hence the light!).

I know the photosensor is probably the issue... I would like to replace it, where can I buy one? Does Home Depot carry these -- my hubby looked (that's where we got the light) and they didn't have them. FYI, our light is Regent Model MD100W, 100 watt bulb.

Any other tips on what might be wrong?

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Old 10-30-02, 06:22 PM
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A lot of times when a mercury light is cycling it tends to be a bulb, But also look for other light sources around that could be fooling the photo sensor. If it is the sensor then any electrical supply store will carry then..
Old 10-30-02, 10:25 PM
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Bekka, as aphares said, if it is cycling on/off every 1-10 minutes it is USUALLY the lamp. But the way you described it, it might possible be the photo cell. The most common for this style lit is a three prong plug in unit that attaches to the top of the head. Every home center I've been in has them, usually by the motion lites, but yours may not, obviously. On theses and other photo cells, there is usually a way to "spin the top" or otherwise partially to completely obstruct the sensor to give it a false sense of night. If it is all the way open, a neighbors lite, car lites in the area etc. might trick it into thinking it is day time. The other parts are a ballast- usually when it fails it fails completly, or an igniter, again USUALLY also a go/no situation.
Old 10-31-02, 03:10 PM
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Thanks. We just replaced the bulb, so that isn't the problem. And no, it isn't cycling on/off, just not coming on each night regularly. So I think the photosensor is probably the problem. I will play with adjusting the exisiting sensor first, then try replacing it.

We LOVE the light ... when it works!

Thanks a bunch for your help!

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