The Technologies don't provide any effect. Researching them is useless!

You should enable at least one possibilty to craft the Multi Furnaces in the Mod Settings. You have multiple choices to adjust your prefered style of play. If you only allow crafting Electring Multi Furnace 3 from Bob's Electric Furnace 3, the Tier 2 version technically exists and must be researched, but cannot be crafted.