On the home repair scale of 1 to 10 (10 being hardest), repairing afluorescent fixture is a 3 or 4... fairly simple but some basic electricalskills are necessary, such as being able to identify wires by color, strippinginsulation from the ends of cut wires, installing wire nuts and readinginstructions. I added the first and last with tongue in cheek... I knowmost of you are not color-blind and most of you can read... or you wouldn't be here!
Here are some common fluorescent freak-outs and some suggestedsolutions! Note that I will be primarily referring to fixtures usingstraight fluorescent tubes in this discussion. Curved tubes work in asimilar fashion but have different mounting methods.
I use the term "bulb" and "tube" somewhat haphazardly andinconsistently. My apologies. Both are correct, though"tube" is the more correct term and probably a little less confusing.
Fluorescent bulbs designed to replace incandescent bulbs instandard fixtures, such as in recessed lights or table lamps, have all the samefeatures of a fluorescent fixture. Alas, they cannot be repaired... theymust be replaced if they become defective.
Finally, let the buyer beware!! Parts for some small fluorescentfixtures may cost more than a new fixture!
Troubleshooting dead or flickering fluorescents...could be a bulb, the starter or the ballast!!
A dead fluorescent can be caused by lack of electrical power (tripped breakeror blown fuse), a dead or dying ballast, a dead starter or a dead bulb(s). Checkfor power first... then the starter (if applicable) and then the bulbs. When all else fails,the ballast should be replaced. Since it is the most expensive item, besure it really is dead!! Ahd check the price before you buy... someballasts are more expensive than new fixtures!!
When flickering is the issue, you still must do the same sort oftroubleshooting since all the same problems that can cause a lamp to notwork can also cause flickering... defective starters, defective bulbs or adefective ballast.
IMPORTANT: Flickering fluorescent tubes can cause the ballast tooverheat and fail prematurely! They can even cause a starter to burn out!Don't wait too long to fix the problem or you may end up with a biggerrepair!
Testing fluorescent tubes...
Thus, the most reliable way to test a fluorescent bulb is to install it intoa knownworking fixture. If you are troubleshooting a 4-tube fluorescentfixture, this is easy! Just remove one of the still-working pair of fluorescenttubes and replace it with each of the questionable tubes, one at a time. 99% ofthe time it will be one of the tubes that is the culprit.
What about pairs of fluorescent tubes?
A flickering fluorescent bulb means that it or one of a dependent pair ofbulbs in the fixture has bought the farm. In many fluorescent fixtures,power is sent through a pair of bulbs. If either bulb is bad, they mayboth flicker or one may flicker and the other show no life.
My philosophy of sensible repair is to always replace both bulbs.
Fluorescent tubes have such a long life and are so inexpensive (with theexception of some of the "natural light" bulbs) that it makes no senseto skimp.
I acknowledge that replacing all the bulbs is not the most economical solution...it's just a practical viewpoint from someone (me) whohas been paid to do this type of work for others (you). Fluorescent tubes are anoverall economical choice when compared to the alternatives! It just makes more sense to change both tubes at once. To receive asecond service call in a month because one of the other bulbs has gone bad isneither desirable from the customer's point of view ($$) or mine (pride in a jobdone right).
However, if both tubes are functional, the problem is with the ballast or,if applicable, the starter. The starter is replaced first, and if that does not solve the problem,the ballast should be replaced. Read on...
Does your fixture have a starter? Maybe...though probably not!
Most modern fluorescent fixtures do not use starters, so you might not findone if your fixture is less than 15 to 20 years old. When determiningwhether your fixture uses a starter, be sure to look underneath the bulbs...sometimes the bulbs have to be removed first to gain access to thestarter. If you do not see a starter... they are never hidden under anycovers or "trap doors"... your fixture is a modern"self-starting" type.
Starters are rated by wattage to the bulbs they will control. If youhave a fixture but have misplaced the starter, write down the wattage of anyof the fluorescent tubes and take that information to the hardware store,lest you be scolded by the mean clerk and sent home without supper... or astarter.
Sadly, there is no way for the home handyman to troubleshoot a starter except byreplacing it. Before replacing the existing starter, though, be sure it issecurely seated in the base by removing and then reinstalling it. Astarter is installed by pressing it into the socket and then turning clockwisetill it locks in place. To remove a starter, press in and turncounterclockwise... then withdraw the starter.
If you own fluorescent fixtures that use starters, always keep a few handyfor troubleshooting purposes! And don't forget to throw away used ones...most of the time it is impossible to tell the difference between a good and badstarter!
Replacing the ballast (or not) may have unexpectedside effects on your wallet!
A defective ballast in your fluorescent fixture may make you want to sink itin the nearest pond! Indeed, the cost of replacing the ballast in afixture may rival the cost of a new fixture... especially if you want to use amodern electronic ballast that lights the bulbs faster, runs cooler and is virtuallyhum-free. (Yes, Virginia, that hum when you flip on thefluorescent lamp is from the ballast, not the bulbs!)
When my customers ask my advice in this matter, I always lean to theaesthetic first. Do they like the appearance of the fixture? If not,add one point to the "replace it" side. Then I confront theceiling repair issue. If the new fixture is smaller or has a different"footprint" than the original fixture, the ceiling may need to berepainted to cover the unpainted area under the old fixture. Sometimes,ceiling texture also has to be touched up after a fixture is taken down!
Smaller fluorescent fixtures, such as those in kitchens to illuminatecountertops or built into furniture, follow the same basic criteria. Sinceyou may have a problem finding an exact replacement fixture (especially if thefixture is very precisely sized), replacing the ballast may be the best choice.
Thus, unless the fixture is absolutely hideous, replacing the ballast isusually the least expensive repair overall when all other factors areconsidered!
Replacing a ballast... just follow the colors!
Fortunately, most modern ballasts have a wiring diagram righton
Universal Lighting Technologies has lots of technicalinfo and even a ballast selection tool that is quite thorough. Visit their site at http://www.unvlt.com)
NOTE: Your new ballast may have the same wiring as your old one, but the wiring colors may differ. Be sure to compare them before disconnecting the old ballast.
Choosing the correct ballast...
Needless to say, when you go shopping bring your old ballast with you toassure you get the correct size. Size is not everything, though.Since you must purchase a ballast that is wired identically to theexisting one, your only choice is the type of ballast, magnetic orelectronic.
Magnetic ballasts are the old-time workhorses in the fluorescent world.They are inexpensive and will give 10 to 20 years of service. There weresome fluorescent fixtures in my father's gas station that were over 40 years oldand still working!!
Electronic ballasts are the new guys on the block. They have somespecific advantages over magnetic ballasts. First, they start more quicklythan magnetic ballasts. Second, they do not hum. Magnetic ballastshum right out of the box. The sound comes from the internal vibrationscaused by the magnetic core which supplies power to the bulbs. As theyage, magnetic ballasts tend to get louder and louder... till they finallyfail. Electronic ballasts are silent out of the box and remain so... tilldeath do you part.
Whether the additional cost of an electronic ballast is worth up to doublethe cost is up to you. I personally prefer the electronic ballasts becausethe hum makes me nuts. It's up to you!
Can you use a dimmer with fluorescent light fixtures?
Yes and no.Yes, there is a specially-designed dimmer switch that will work with somefluorescent fixtures. However, this type of dimmer is"ballast-dependent", meaning that each brand of fluorescent dimmerwill only work with certain ballasts from certain manufacturers.In other words, trying to find a dimmer to match your fixture may be amind-numbing chore. The ideal situation is to choose the dimmer and thelight fixture together to assure compatibility. Also, these dimmers willnot work for incandescent fixtures. You cannot mix fluorescent fixturesand incandescent fixtures on the same dimmer switch.
The "No" part of this question is that the "conventional"dimmer switches you can purchase at the hardware store are designed forincandescent lighting only, not fluorescent lighting. If you attempt touse them, the fluorescent fixture may work but only in the full-on position, ifat all.
Leaving Fluorescent Lights On... An Energy Saver??
Not necessarily! As with most things in life, moderation is the key tolongevity! Read our article on the facts and myths around the greatfluorescent shutoff! Click HEREfor the full article!
Other resources...
If you want some good technical information of testing ballasts, the mostcomplete source I have found on-line is The Lighting Center, at http://www.thelightingcenter.com/lcenter/technica.htm.
If you would like an in depth look at how fluorescent fixtures work, visit"How Stuff Works" for a detailed, high brow explanation, at http://www.howstuffworks.com/fluorescent-lamp.htm
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