Furnace problems?

[nfair Profile]

I set up a chest and hopper fed furnace in my leoville lot. It's reliably smelting at less than 50% efficiency. I started by putting in ~3500 sand and 35 lava buckets to smelt into glass. A day later I had ~1600 glass blocks, all lava buckets had been consumed and ~1700 sand remained in the feed chest/hopper. Thinking I simply miscounted I added more lava buckets (16) and set to smelting again. This time about 600 glass blocks were produced after all lava buckets were consumed.

As a last trial I used a single lava bucket, the furnace only smelted 43 sand blocks into glass. Each lava bucket should be capable of smelting 100 blocks. I've seen it produce only 99 blocks occasionally.

Are hoppers known to cause problems when feeding furnaces? Is it a minecraft issue, a server specific issue, or am I missing something that makes it unworkable?

[spkarrer Profile]

It might also have to do with what happens when your furnace is loaded/unloaded in memory. To save space, the server probably only saves the items in the furnace, not the state of the "fuel"

Have you tried hanging around it for the full smelting time?

[nfair Profile]

I think that's the most likely situation, but it's either new or triggered by hoppers. In the past I have done plenty of 100 unit smelting runs, keeping the chunk loaded only sporadically throughout even multiple real life days in order to get all 100 items smelted. So in the past having the chunk go unloaded several times during a smelting session was fine.

My intuition says that having the chunk go unloaded while hoppers are feeding/draining a furnace is causing small fractions of smelting time to disappear. It may be related to updating the furnace more frequently with a hopper feeding it. I was part way through an experiment when the server went down tonight where I kept an eye on multiple furnaces and they all were producing at 100% while I was there.

[thornton77 Profile]

I think they added some randomness to the furnace at some point. The Coal to Ore count use to always be 8 coal were consumed for every 64 stack. After one of the 1.4.x updates I noticed it wasn't always 64 for 8 it was sometimes 9 or 7 for a 64 stack.
This is when I was building the huge building and I had 36 furnaces going at once

[asim0v Profile]

I think they added some randomness to the furnace at some point. The Coal to Ore count use to always be 8 coal were consumed for every 64 stack. After one of the 1.4.x updates I noticed it wasn't always 64 for 8 it was sometimes 9 or 7 for a 64 stack.
This is when I was building the huge building and I had 36 furnaces going at once

No, it has been like this for a while. Try it out in single-player and you will find that it's always 8 coal per stack. I believe it's just a bug with multiplayer servers and timing or lag.

[hamy02 Profile]

I just now had a bug with furnaces. I had 62 coal in a furnace as fuel (not being used). I put one coal in, but instead of turning to 63 coal, it turned to 10. :/