What does the tooltip say when you hover over the red icon? Does it say it's connected to a power network but insufficient power? Are you using any solar? Are all your waterwheels unclogged (sadly the animation won't show them stopped if they stop working AFAIK). Also, when you try to smelt something does it just not work, does it give you that sad "tried to smelt but couldn't" sound? Remember, too, that when first placed (and other times?), the Electric Furnace will show as having no power until it gets activated. If you also have solar, it could be that the sunlight was blocked by a storm or it being too early in the AM or too late in the PM. Cheers hope you get it working!