I've just gotten a Gralab Model 300 darkroom timer for a good price, but note after receiving it that the data plate shows: 750 W, 6 Amps, 3 Amps "T". I presume "T" refers to the timer switched circuit. I plan to use it to switch a Zone VI cold light in my Omega D2.
I'm a little concerned at this low rating, since the inductive load of a cold light gives it a very high startup draw relative to its steady state condition, as well as making it prone to arcing on switch contacts when switched off. I don't know the rating of the Zone IV unit I have, though, and it doesn't seem to have a data plate.
Based on the size of the tube, it can't draw much more than 20 W; if that's the case, even allowing for 10x rating to handle startup load and inductive cutoff, the Gralab's relay should be fine. However, I don't know if the cold cathode tubes used in cold lights are really comparable to the common fluorescent lights I'm more familiar with; the light is bright, but not any brighter than a 15W fluorescent desk lamp I have here.
So, my concern is, will I be overloading anything running the cold light from this darkroom timer? The heater circuit for the cold light will, of course, bypass the timer to remain on during the entire printing session.