Flourescsent Tubes Dying Mystery

wallix

In my kitchen I have a fixture that holds 4 4ft fluorescent tubes. About 2 months ago I bought 4 40w GE Reveals to replace my old garish 30w tubes. For 2 months everything was fine, but then the center 2 tubes would not fire (They are paired 2 on the outside and 2 on the inside), but after a bit of sputtering at least the outer 2 would come on. You can see the center tubes want to turn on, but they give up and concede to the outer 2. I then swapped the pairing and the inner 2 would not work together as a pair - even on the outside. So I went to Lowe's and exchanged them for a new pair. It worked! Or so I thought. After a week, the center 2 struggled to fire again and eventually the outer 2 would turn on. I did the swap, and the new ones seemed to be trashed. They will not fire together, even on the outside pair. It's the exact same problem again even with brand new lights.

I can't figure out what is going on. It seems like something in my fixture is ruining anything that goes in the center-pair now . Is 40w too much (old ones were 30w).

Missouri Bound

Sounds like you have the wrong tubes. Open the fixture and look at the ballast....it will tell you what tubes you should be using. Another couple of things that can shorten bulb life is weak tombstones or improper seating of the bulbs.

Code05

Or the ballast is dying.

Missouri Bound

Was there a problem with the old tubes? If you did put in the wrong tubes, you may have also have done some damage to the ballast(s). I think Code05 may have hit the nail on the head.

AllanJ

If just the ends of the tube light up as the tube tries to come on for long periods of time then the tube will be trashed in short order.
You definitely put the wrong tubes into the fixture. The results can be unpredictable.

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wallix

Thanks for the replies.

I checked and both the ballasts are rated for 40WT12 lights which is what these Reveals are. I think the seating is OK, but I'm not sure about the tombstones.


Is there a quick way to rule that out or is a new fixture in order? This fixture came with the house in 2002.


I'm leaning towards the ballast theory myself. The old tubes did not have this problem. But keep in mind that it took over 2 months for the first set of Reveals to malfunction. Now it seems like it's going to happen regularly. But after actually checking the ballast, it would seem the original tubes were underrated at 30w.


It's not just the ends fortunately. The blinking seems to be even throughout the tube. Although when I put all 4 in I can see the rings passing through the tubes of the middle set as it tries to light (then gives up).

I have a feeling if I went out and got 2 more Reveals that all 4 would work in harmony for about a week again, then the middle set would die off. Does this sound like a ballast issue?

Missouri Bound

WEll...if you like the fixture, you could change the ballast.

Missouri Bound

Your new lamps are t-12, right? If you like the fixture, change the ballast out. Too bad it's T-12....the T-8 technology is much better, cheaper, brighter......blah blah blah...

wallix

I hate the fixture actually. "Generic" is an understatement. When I return these lights I'll check out the world of T8.

AllanJ

Also if a fluorescent tube blinks a lot it will fail in short order.

__________________
The disadvantages of crab apple trees. In summer, the apples are too sour to pick and eat. In winter the birds come and leave dropping all over the place.

Missouri Bound

Sounds like you are doing things in the right order. First the bulbs....it's usually the bulbs. If they light at all there isn't a wiring problem. If they flicker or need to be twisted or tapped to come on, it's most likely the fixture "tombstones". The ballast is usually the last step, unless there is a grounding issue.

wallix

When I took the ballast cover off I was shocked at how dirty, greasy, and brown the wires were (One of them even looked burnt). It was definitely just thrown together by the builder. I'm wondering if there was a problem with that ballast all along and since the old tubes were actually only 30w that the problem never revealed itself till I put in a 40W. Like Missouri Bound mentioned, I think a T8 overhaul is in order. I can live with the 2 working T12's for now.

The mystery to me still is:

1. Why do new lights work wonderfully for a week?
2. After a week, what would cause the 2 middle lights to consistently and permanently fail?

Code05

A dying ballast.

frenchelectrican

Majorty of the F40T12 bulbs with the ballast which I useally run into they are two lamp ballast which it is most common due you describing outer two and inner two so I know a very good chance you have rapid start ballast so you will have to find a bad ballast.

The surefire way is convert to single ballast 4 lamp T-8 verison F32T8 do give little more light than old school 40 watter plus what more they are electronic so they are very quiet and no flicker.

But if you want to convert it you have to follow the wiring diagram carefull plus you will have to shunt the tombstone if that is electroinic verison.

Merci,
Marc

__________________
The answer will be based on NEC ( National Electrical code ) or CEC ( Cananda Electrical code ) or ECF ( Electrique Code France )

ddawg16

While your at the store looking at T8's....have a look at T5's as well....or, maybe consider other lighting options....maybe recessed cans....then you can use any combination of CFL's....lots of color and wattage choices.

If you do go the can route....look for cans with the GU24 base....that way you stay compliant with energy requirements.

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