Recessed PL lamps seem dimmer at times

Status
Not open for further replies.
R

rlwiley

Member
Why would recessed cans that have 2 - 4 pin 26 watt PL lamps seem to br dimmer during different times of the day? The maintenance man seems to think that it only happens when it gets cold. The problem with this is that it has not been below 50 degrees yet this year and they were also complaining of this during the summer.

This is what I have learned so far.

1st. electronic ballasts have a rating that is at 0 degrees.(is it a true statement to say that temperature below 0 degrees only affects the striking of the lamp and not the light level of the lamp after it is burning)
2nd. These lights are in a room that has no windows, skylights, etc.
3rd. You do not come in from outside and enter directly into these rooms.

Any comments would be greatly appreciated in advance.
 
I noticed the same thing at our office. I finally got out a light meter to prove it to myself. Then later someone shut off a large floor fan that was on a separate circuit. The lights slowly came back up to "full" brightness. Turning the fan back on made them slowly dim.

I never had the time to check the voltage but apparently they are VERY sensitive to voltage fluctuations!
 
The ballasts are affected by the ambient temperature, and the light output will change with ballast temperature.

The specification of lowest ballast operating temperature is in regard to the (typically) lowest temperature at which the ballast will successfully strike the lamp into operation. From that point on, the ballast will typically increase output from the lamp as both the lamp and the ballast warm up.

Dan
 
Are they installed in an air handling ceiling? If so, whether the furnace or ac is presently running may effect the lumen output of the lamps.
 
I have had a simular experience on certain floors in my large office building. The problem was due to an imbalance of static air pressure between the ceiling and the office spaces. The imbalance would cause air flow through the compact fluorescent fixture and cause it to dim. Balancing of the supply and exhaust fans helped in my particular situation.
 
When CF lamps are first turned on, it takes them a couple of minutes to get to full brightness. They are also very sensitive to temp. changes.

Recently looked at a remodeled office, and all the 2x4 lights that had a diffuser right next to them were a slightly bluer color.
 
Any ideas on going about finding a solution. I have never personally seen this with my own eyes but the customers are saying that it is a big difference at times.
 
If (IF?!) PL lamps are directly affected by temperature how would a lighting designer be able to accurately light a space based on a how many foot candles an owner requires? You would think that the lighting manufacture would be required to have some sort of a chart that tells how many lumens the fixtures put out based on the amb. temp.
If this problem is temperature related why would it affect every fixture at the same time.
 
I have CF spots in my cans in the bathroom.

They are noticably brighter at times. Never been able to correlate just what it is.

Bob,
Do you notice if the brightness level changes when the bathroom door is held opened.?
 
rlwiley said:
If (IF?!) PL lamps are directly affected by temperature how would a lighting designer be able to accurately light a space based on a how many foot candles an owner requires?
Click to expand...
All fluorescents are affected by temperature... but PL's certainly seem more sensitive!
 
Status
Not open for further replies.
Top