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fluorescent light humidity trouble

kentlakesconsulting's picture

i installed a lrg (36x36 double u-tubed) fluorescent kitchen light fixture a year ago, and it was working fine until a couple of mths ago.

now, whenever the humidity is high (whether via a rainstorm or simply summer heat) the light does not want to switch on at all OR switch on fully (you'll see a faint start-up on one side of the fixture, which does not fully illuminate. and the other bulb side stays dormant)

i've replaced both 2-way switches, but this did not solve the prob

could i be dealing with a moisture prob from above, in my attic? while this might help explain a prob with the rain, it does not cover those days of simple high humidity.

my roof is "new" (10 yrs old), but i know i have some soft/rotting fascia

many thx, in advance, for any assists

(post #84069, reply #1 of 15)

Is the metal frame of the fixture properly grounded?


There is no absurdity that human beings will not resort to in order to defend another absurdity. -- Cicero


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #84069, reply #3 of 15)

thx
if it was not, wouldn't the light not have worked at all?

thx

(post #84069, reply #5 of 15)

If the frame is ungrounded it often makes it harder for the lamp to "ignite". The startup of the lamp depends to an extent on the capacitative coupling between the lamp and the fixture.


There is no absurdity that human beings will not resort to in order to defend another absurdity. -- Cicero


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #84069, reply #7 of 15)

many thx for the detail
i'll re-ground and see what gives

(post #84069, reply #9 of 15)

The idea about cleaning the lamps is also a good one. And sometimes the blasted things just need a hug -- they're feeling lonely.


There is no absurdity that human beings will not resort to in order to defend another absurdity. -- Cicero


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

(post #84069, reply #11 of 15)

You can test it by holding a piece of (ferrous) sheet metal along the tube during the ignition cycle.

(post #84069, reply #2 of 15)

On linear tubes that have been around for a while, specially in a kitchen, I find that the bulbs will get coated with grease and dirt and that keeps them from striking when it is humity.

I have had good luck cleaning the bulbs including the ends around the pins and also the face of the socket.

Rubbing alcholo is good for that.

I did that in one kitchen with 2 sets of 4 ft fixtures.

But there was one with 2x2 with U-tube. First of one those that I worked on. It has a new bulb that the HO son has just replaced. I replaced the ballast and it did not help.

End up trying a diffrent brand of bulb and it worked fine.

There was a difference in the dsigns. The one that did not work right had a metal foil tape that ran the lenght of the bulb and was grounded by a mounting clip that helpd the bulb in place. The one that worked did not have that tape.

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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
. William the Geezer, the sequel to Billy the Kid - Shoe

(post #84069, reply #4 of 15)

i'll give that a shot

many thx

(post #84069, reply #6 of 15)

clean the bulbs contacts and sockets..

 


Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming


WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!

"Some days it's just not worth chewing through the restraints"

(post #84069, reply #8 of 15)

many thx, sir

(post #84069, reply #10 of 15)

after you clean them remove any oxidation on the tabs/pins/sockets with a pencil eraser...

 


Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming


WOW!!! What a Ride!
Forget the primal scream, just ROAR!!!

"Some days it's just not worth chewing through the restraints"

(post #84069, reply #12 of 15)

Try replacing the ballast, then worry about the rotten fascia...etc. A fan in the kitchen will help the humidity.

(post #84069, reply #13 of 15)

cleaning the pins and sockets solved it

many thx everyone

(post #84069, reply #14 of 15)

What a timely topic.

This summer, on really humid days, our kitchen light has also refused to turn on. I went out and bought bulbs and was about to replace them when the light started working again. So I never did. Then another rainy day and it wouldn't turn on again. It works 95% percent of the time, but on really humid days it doesn't.

I'll have to try the tips here.

(post #84069, reply #15 of 15)

Those sockets are called tombstones.