Fluorescent light fixture is hot.


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Old 03-13-17, 06:18 PM
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Fluorescent light fixture is hot.

I have a bunch of old 48" fluorescent light fixtures. I have one with two bulbs that hangs three feet from my unfinished basement ceiling. I use it to provide light to my seedling vegetables. I noticed today that the top of the fixture is really pretty hot. I did some reading on this, and everything that I see is related to ballasts. Today I took the ballasts out after the lights got going, but the top of the fixture is still pretty hot, although it seems that the "hot spot" is no longer on the end where the ballasts go, but is more toward the center of the fixture. Any ideas what's going on here, and what the risk is in continuing to use it as is?
 
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Old 03-13-17, 06:34 PM
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How did you take the ballast out ? It's still needed to keep the fixture running.

Ballasts run hot. Older ballasts run very hot. In this case you can equate heat with money wasted. Actually the heat is usable in the winter.
 
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Old 03-13-17, 07:19 PM
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Well I guess what I thought was the ballast is not the ballast. I'm talking about the little cylindrical things that still out of the side, and you just twist and remove them. I have one set of lights that won't turn on until I take them out.
 
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Old 03-13-17, 07:25 PM
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Do you mean starter? If so the fixtures must be very old.

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If you changed ballasts the newer ones don't require a starter but the ballast must be connected according to the diagram on the new ballast not how the old ballast was connected.
 
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Old 03-13-17, 07:34 PM
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That's it. So, can I continue to use my lights as they are just to get through the next 8 weeks? I really don't have time to put in new ballasts, but I do have time to move fixtures around, and I have a lot of them.

And yes, they are old fixstures. My house was built in 1948, and my parents bought it in 1961, and put on an addition in 1964, so they are at least 50 years old.
 
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Old 03-13-17, 07:44 PM
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If they work no problem. If it was the starter that was hot it may be sticking. It is basically a thermal switch that shorts the ends of the tube for a few seconds to start the light. There is a heating coil and a bimetallic strip. The heating coil heats the strip and opens the circuit. The heating coil remains on to keep the circuit open. That may be the heat you are feeling.
 
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Old 03-14-17, 02:36 PM
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So, there is no problem that my ballast runs hot, because I have it so far away from anything that is a risk for fire?
 
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Old 03-14-17, 02:43 PM
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As long as the back of the fixture is not against anything flammable.... you'll be fine.
 
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Old 03-14-17, 05:07 PM
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Thanks. I think this is the 15th project I have completed with guidance from these forums.
 
 

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