Factorio Forums

With mods, it is possible to make an inserter point to the same machine for its input and output. In this case, it behaves a little inconsistently: an inserter will happy move the output of a machine into its fuel inventory for burning, but not into the ingredient inventory for reuse. They should behave consistently one way or the other; bobingabout said in Discord he thinks it would be nice to be able to move things from products to ingredients.

Thanks for the report however there is no logic which prevents this from working. Inserters don't care or even know about the possibility that the pickup entity is the same as the drop off entity.

Sounds like priority of input inventories is fuel > input.
To have inserters feed from output to input instead of fuel only the priority would have to be changed. There's no vanilla recipe where this change would matter, though it might break some mods like burner assemblers.

The kovarex process should be a test for this. Does an inserter put the calalysts back from output to input? There is no fuel getting in the way.