What datapack(s) do you have installed (including ones made by me- include version if possible).
Mechanization: v4.2.4
Ensure the datapack is loaded with /datapack list
It is.
What environment are you running the datapack? (Vanilla single player, Vanilla multiplayer, Forge, fabric, spigot, bukkit, paper, optifine, realms, etc). Please specify exact Minecraft version as well.
Forge 49.0.49 (with no other mods installed) Minecraft 1.20.4
What if happening vs. what you expect to happen?
When I place raw tin into a normal vanilla furnace it just starts to smelt without any fuel, the furnace also does not show that it is lit.
/datapack list