Dimmer, are amount of leds limmited

Is there a limit to the number of leds you can connect to a dimmer as long as you stay under the total of 200 watt ?

my dimmer died, at first i tested it on 6 * 6w leds(240v) worked fine, then i hooked it up in the living room with 16 * 6w, at first on off ok, then tried dimming and all of a sudden a buzzing from the dimmer and when it stopped the light was always on, factory reset no help, still always on.

?