Waiting for source items?

[&rew]

Here's a screenshot:

https://steamuserimages-a.akamaihd.net/ugc/1178202144324046962/458E533A1FA15BC468B59EF06893D142A99A4C7F/

As you can see, the third inserter down will put the iron into the furnace, and the next arm will put that iron plate into the next furnace, but it won't put the steel plate onto the output belt. The other three rows of furnaces won't grab anything, and they all say "waiting for source items". I have no idea why this is happening. It happened the other day when unloading a train as well, and I managed to get it working by picking up the train car and placing it back on the tracks. It could be a bug, but I'm assuming first that the game is working correctly and that there's something I'm missing. Is there something I'm missing?

[Fel]

Look closely at the flashing red triangle, it tells you what is wrong.
This particular one means "no fuel" since they don't have access to coal.

You need to either manually bring coal to them or to run a belt with it on the left of the belt for steel plates and use red inserters to grab it and put it into the furnace (or the other way around and use the red inserters to send the steel plates 1 tile further on the belt mentionned for the coal and have the coal on the near belt).

[&rew]

What? That's ridiculous. I've done coal + other item on one belt with standard inserters a million times. You don't need long inserters until you hit more than 3 inputs for one output. The leftmost furnaces should be grabbing coal from the furnace to their right. The furnaces on the right have coal but won't grab any iron, which is why you don't see the iron plate on them like you see the steel plate icon on the furnace in the first column, third row. Only the third row inserter is making an effort to grab iron, but they're all set up the same. The thing that it tells me is wrong is that it's waiting for source items, not that it needs fuel.

[Fel]

The inserters on the right definitely grab the iron ores, we see an inserter with iron ores in its hand in the screenshot you provided, they stop when the output of the furnace is full or when there are already 2-3 ores in the input.

Inserter are not allowed to take coal from furnaces, they would be putting it on the belt together with plates if they were allowed to do that, so you need to bring coal with belts from the other side in that setup.
You can definitely share the belt that would get the steel and put the coal on the "near" side but you would need to make sure to filter the belt down the line to only allow steel to continue through.

[&rew]

Now it looks like this.

https://steamuserimages-a.akamaihd.net/ugc/1178202144324292901/438D21D63A64A319D0E460BB6A72CAD9EDFE76D4/

Everything has fuel, only the third row is grabbing and outputting items.

[Fel]

That's very weird, are the other 3 sets of furnaces empty?
If they are maybe try to mine and rebuild the inserters feeding them, there are some weird cases where they get stuck.

[&rew]

Yeah, the furnaces had iron plate in them still from before I daisy-chained the furnaces for steel. Weird that that gets them stuck.

[Fel]

A sudden idea popped up but is it possible that those iron plates were in the input of the right furnaces instead of the output?
That would explain why nothing was put in ot taken out at least.

[The Chaotic Coder]

Originally posted by Fel:

Inserter are not allowed to take coal from furnaces, they would be putting it on the belt together with plates if they were allowed to do that, so you need to bring coal with belts from the other side in that setup.

Wait, inserters can't pass coal from one furnace to another any more? I used that tactic with the old style boilers loads of times, and I'm almost 100% sure you could do it with furnaces too. They'd pass coal to another furnace, but they wouldn't unload it onto a belt... I'm pretty sure that's how it worked. Or maybe it was just burner inserters?

[Fel]

Boilers and burner mining drills can pass around coal but not furnaces.
The reason being that outside of the coal there is nothing that can be taken out with inserters with burner mining drills or boilers so it's fine for them to take out the coal but for furnaces where the inserters take out the plates the problem would be that the belt would end up with both coal and plates.

EDIT: Similarly inserters can take research packs out of labs but you can't take the ingredients from an assembler out like that.

[&rew]

Originally posted by Fel:

A sudden idea popped up but is it possible that those iron plates were in the input of the right furnaces instead of the output?
That would explain why nothing was put in ot taken out at least.

Yes, they were. Originally, the iron plates were sent there as inputs to make steel plates. Then I switched it up so it had its own supply of raw iron to make iron plates, to make steel plates. Man, what a weird problem. But that explains it. Thanks!

[KatherineOfSky]

Originally posted by jchardin64:

Wait, inserters can't pass coal from one furnace to another any more? I used that tactic with the old style boilers loads of times, and I'm almost 100% sure you could do it with furnaces too. They'd pass coal to another furnace, but they wouldn't unload it onto a belt... I'm pretty sure that's how it worked. Or maybe it was just burner inserters?

The only "pass through" item in vanilla is science packs. Transferring coal was in various mods, including Bob's, so maybe that's what you are thinking of?

[Fel]

Outside of labs, gun turrets, boilers and burner mining drills also work like that even in vanilla so it's not always consistent (I mean, if it was "only has 1 slot" then burner inserters should also act like that but you can only input, not output with their fuel slot).

[The Chaotic Coder]

Originally posted by KatherineOfSky:

The only "pass through" item in vanilla is science packs. Transferring coal was in various mods, including Bob's, so maybe that's what you are thinking of?

That may be it. I've been running Bobs/Angels for so long, I sometimes forget what's Vanilla and what isn't.

Thanks!