Lamps: Leave on or turn off?

[GregK]

Hello everyone, and thanks in advance for your advice.

We have several Agilent 1100 and 1200 and a couple Beckman HPLCs. It has been our practice to turn off our UV lamps at the end of a sequence. Then later turn them back on. Sometimes this is only a few hours, sometimes it is a few days.

I seem to recall being told at one time a minimum "off time," that the act of turning the lamp on is hard on it, and sometimes leaving it on is better.

I can't recall what that minimum "off time" was, or where I heard it (Agilent maintenance training?).

What do you all recommend?

Thanks again,
-GK

[Hollow]

we usually shut off the lamps at the end of a sequence, as programmed in a shutdown method, where we prepare the column for (possible) storage (change the solvent to 100% organic, maybe with an intermediate step of 100% water if buffer was used).

I once heard of two considerations (Waters service):

1) short shutdowns may reduce the lifetime of the lamp

but

2) leaving the lamps on can lead to dead optics window (over the years), which then will be much more expensive to replace

[JGK]

we usually shut off the lamps at the end of a sequence, as programmed in a shutdown method, where we prepare the column for (possible) storage (change the solvent to 100% organic, maybe with an intermediate step of 100% water if buffer was used).

I once heard of two considerations (Waters service):

1) short shutdowns may reduce the lifetime of the lamp

but

2) leaving the lamps on can lead to dead optics window (over the years), which then will be much more expensive to replace

Been using Waters equipment for a number of years now and routinely shut off the lamps at the end of the sequences. So far I have not had a problem with shortened lamp life.

I have found that the 2487 detector optics window will require replacement every two years (the windows "solarize" and become "foggy") and this has affected analyses more than any lamp problems.

[HW Mueller]

Some manufacturer technition recommended to leave the lamps on when the pause in their use is around 2h, and shut them off if the instrument is not used for more than 2h.

[sfe-co2]

I read the above with interest.

However, the arcing in the lamp may be quite damaging if constantly turning it on and off in the short term (say, within ~2hrs). This shortens its serviceable life. In this case, I'll leave it on because lamp voltage and energy output will still be stabilized for your next analysis. Beyond that, turn it off.

Hope the above helps.