Can someone tell me how the contents of a furnace affect a comparator? I want to create some automation in vanilla Minecraft, but don't know how the mechanics work.


This page has a paragraph specific to the power output through a comparator on a furnace.

It's pretty confusing, though.

Basically, for the full 15 signal you need something in all 3 slots of the furnace. If you're feeding in smeltables and fuel (assuming they are in the right places, and full), then anything above 10 would mean that there is something that has completed smelting.

That is probably over-simplified, but I hope that helps.

To further attempt to answer your question; The contents are summed and the resulting value of all contents are output through the comparator.

| improve this answer | |
  • and there is no way to just for it to just judge the amount of coal for instance by putting the comparitor on a specific side – Flaunting Jul 23 '14 at 15:30
  • 1
    Perhaps someday, but currently no. I expect Mojang isn't interested in easing the automation. They're providing very basic tools that do very basic things, then allowing human creativity to work out solutions for complex problems. It's part of the fun, but I agree - it's a frustrating kind of fun. Not fun for everyone. – Luke Jul 23 '14 at 15:37
  • 1
    I put a comparitor on a hopper that feeds coal into the furnace. You don't get the amount of coal in the furnace, but you can tell when the feed hopper is empty. – Therealstubot Jul 23 '14 at 20:08
  • That is a very good solution. That could cause an issue if you use more than one fuel type, because there's no way to tell in that case if you have a stack or less already in the furnace. With only one fuel type, that should work perfectly. – Luke Jul 28 '14 at 21:35

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.