Fluorescent light flicker - t12 in a new light

[JHZR2]

We have a fluorescent light over our washing machine and dryer. It plugs into an outlet and uses the standard size fluorescent tubes. 40 W T 12 I believe. Based upon my understanding it is acceptable to run T12 bulbs in these new style electronic ballast lights. Our old one failed but the tubes were perfectly fine so I reused them.

When I start up the light it works perfectly fine, bright light no issues. But if we leave it on for a long time it starts to flicker with a 60 Hz type flashing. It doesn't turn off or go dark, it just loses intensity to look like a flicker at a very rapid rate.

The odd thing is that if I turn it off via the pull chain and then start it back up again it will not turn back on. I have to unplug the light and then plug it back in, at which point it starts up and puts out perfect light again without any flickering.

My understanding is that T12 bulbs are acceptable for use in the new fixtures. However I believe that the T12 bulbs are 40 W while the T8 bulbs and 32 W. The ballast in the light definitely feels warm to the touch, but I can't say that it is excessive. The flickering occurs only after being on for a long duration.

Any thoughts on the cause of this??

Thanks!

 

[Gotch]

It depends on if the balast is rated for T12's. Electronic or not the balasts still have ratings. By the sounds of what you are describing, the balast is not rated for T12s.

Why not buy T8s?

 

[JHZR2]

Really just because I had the t12s and they worked perfect if not left on for hours.

Unfortunately none of the labeling ofthe fixture gives any real clue, not even a V/A rating.

 

[electrolover]

Look at the ballast. It will list what lamps it can support. Sounds like you have a bad ballast or the wrong lamp

Most t8 ballasts cant support a t12 even though the tombstones will except either lamp

 

[eljefino]

Check your grounds. Flourescents like them. If you touch the bulb glass and things improve, it's partially grounding through you!! I tried a pair of T12s (because I had them-- found them in the attic/ 40 year old classic GEs) on a WM LOA cheapie shop light with electronic ballast and it had that "dancing" phosphor look even after they broke in. You did give your bulbs time to break in, right?


There is a "good reason" you shouldn't run T12s in T8s and vice versa if not rated for it. Something about the fire-off arc-striking voltage being more/ less and harming the "modern" part of the equation.

 

[Rand]

most likely the ballast. and good ones are expensive..

cost more than a cheapie fixture with bulbs and ballast.

but the cheapie fixtures dont work in my basement.. too cold.

 

[HerrStig]

A ballast is nothing more than an inductor which lowers the running voltage of the lamp by inductive reactance. The
'starter" shorts the ballast for starting, when higher voltage is needed and then opens, so current must flow through the ballast. Very little can go wrong with a coil of wire wrapped around a core but the value of the ballast must be correct for the current draw of the lamp.

 

[Quest]

Try your best to identify what type of ballast you have.

If it's electronic style, your ballast maybe faulty.

If it's good ole reactor type, replace it.

Also: observe the type of tubes that replacement ballast supports.

Most newer electronic ballast T12 type only supports lower wattage types such as 34W T12, etc. so you have to get the right one.

Q.

 

[VNTS]

is the ballast for T12 or T8?

Is is Rapid start( has coil heat transformers), how old are the lamps?

Your F40T12 run on 400 mA current, need the coil heat.

I would suspect you have a ballast issue.

What does the "etch" on the lamp say, 40W, 34W ?

 

[electrolover]

Boy there sure is a lot of electricians here......

 

[spackard]

Also, you have to look for them in my area, but there are regular electronic ballasts and low temperature (I think 0°F) electronic ballasts. In the winter (30°F), my garage light starts much better with the lower temperature ballast.

From another website: Lamps will operate down to 10°C (50°F) for standard lamps and 16°C (60°F) for energy saving lamps.

So, maybe it's a combination of standard lamps and a 0°F ballast.

 

[JHZR2]

That's all it says. Our basement is pretty cool, likely is in the 50's.

Ill look at the bulb etch, pretty sure they are Philips Alto, less than 6 years old.

 

[DBMaster]

"Unpuged?" Maybe assembled in the USA, but obviously not spell-checked here. LOL

 

[VNTS]

That is cheap LOA ballast for 2 F32T8 lamps.

That is probably your problem. Go spring for a couple F32T8 bi pin lamps.

 

[spackard]

Googling, it says:
Model 8045E-XX, electronic ballast; 2-32W T8 or 2-34W T10* or 2-34W T12 lamps

http://directories.csa-international.org/xml_transform.asp?xml=certxml\103653_0_000-3451-81.xml&xsl=xsl/certrec.xsl

For compact fluorescents, LOA is a joke. I wouldn't trust anything else they make, but I only have first-hand experience with their CFLs.

 

[JHZR2]

So what is the brand I want if I get another light when this one goes?

 

[spackard]

This one is a Philips electronic ballast for (2) F40T12 bulbs:
http://www.homedepot.com/h_d1/N-5yc1v/R-...;keyword=496786

Philips Advance AmbiStar

Almost guarantee you'll have to do some modification of your fixture to fit it.

What I did was go to the local Home Depot and rummage through all the electronic ballasts they had on the shelf. I bought one that made the lamps both noticeably brighter and last far longer than they had been lasting. Then, I did my wife's office, and it became a lot brighter and they haven't had to replace lamps for years.

The electronic ballasts are lighter in weight, smaller in size, no 60Hz whine, and seem to make the lamps last a lot longer.

I'm not so much recommending the Philips as I am sharing that LOA CFLs have been bad.

 

[VNTS]

Look for ballast by Advance, magnatek, TriadUtrad, those were the good ones back when I worked in the field.

You want something for 120V input, 2 lamps, for F40T12 or F34T12
Rapid Start, 430mA lamp current

http://www.prolighting.com/relb-2s40-sc.html

 

[JHZR2]

I dont think Id buy one for T12 bulbs since T8 seems to be better.

I piece parted this together because IIRC the box siad it could take the bulbs I had, and so why buy anything else.

Left on for just a few hours this doesnt happen, so Im not terribly concerned, it is a laundry room, not a work space. But thanks for the recommendation, for when the time comes.

of course by then we may be able to get cheap LED tubes!

 

[VNTS]

Either buy a good fixture with ballast and lamps.

Or keep your fixture, 4 ft bi pin lamps will fit weather T8 or T12.

get a couple Sylvania F32T8 Octron, 3000K color temp, good quality.

http://www.ballastkit.com/index.php?main_page=product_info&products_id=1094

get a ballast like this

http://www.prolighting.com/b332punvhp-a.html