Dimmer swich to chandalier replaced it worked fine 3 hours later no light nothing

Sounds like it failed, either either due to it is overloaded, or it is a junk brand.

Let me guess, made in China?

What is the wattage rating of the dimmer?

What is total wattage of lamps in fixture?

Could also be as simple as a loose wire, right? Check all connections under the wire nuts... one of the wires may have come loose.

Otherwise, answer Tkrussell's questions, OK?

Mark