All fluorescent fixtures, before dimming, should be burned in for at least 100 hours. If that is not done, it will dramatically shorten the life of your fluorescent lamps
, as well as lead to other problems with the dimming curve. Turn on the lights, and leave them on for the 100 hours....
Dimmers usually have to have different settings (or a completely different module) to be able to dim fluorescent fixtures properly - depending upon the type of ballast. Even with the correct ballast fine tuning the dimmer curve is critical to proper function.
There are 3 main types of fluorescent dimming ballasts, that I know of.
This type of ballast is able to dim just like a regular incandescent lamp would - with a hot and a neutral running through a dimmer. (In ETC world a D20) The settings on the dimmer usually need to be different than they would be for an incandescent fixture, but it can be done nonetheless. The Advance Mark X (read Mark 10) ballast is one of this type.
This ballast takes a different type of dimmer module. (In ETC land, it would take a D20F) This ballast uses a dimmed hot, a constant hot and a neutral.
4 Wire ballasts
This ballast can use a standard dimmer module (in switched mode) or a relay module. There also needs to be a 0-10v analog source that works in conjunction with the dimmer or relay. The switched source provides constant power to the module with the 0-10v provides the control signal while the ballast does the actual dimming based upon that signal.
See this thread
. Strand C21 dimmers seem to require "Advance Mark X" (Mark 10) ballasts.
A perfectly adjusted dimmed fluorescent fixture will never completely dim on and off like a incandescent lamp. When the fixture is dimmed off it will drop to a very low intensity then suddenly blink off. When turned on, they will blink on to a low level then dim up gradually. Also remember that fluorescent fixtures require a certain amount of warm up time depending on a variety of factors. Turning on fluorescent lights can take anywhere from a few seconds to 2 or 3 minutes to reach full intensity. While they are warming up, it is not uncommon for fluorescent lights to have a pink or purple appearance. For these reasons fluorescent house lights can be distracting, unpleasant in appearance, and make quickly turning on house lights impossible.