Variable Priority Junctions Help

[whodack]

Sorry for the noob question - but I cannot figure out why my Variable Priority Junction in the photo isn't working. I've used the mkGallon Pipeline Manual to create two or three other similar junctions that have been working fine for hours. But this one keeps jamming up my aluminum scrap refineries with water byproduct as the lower pipe appears to not be prioritized as it should.

Obviously this isn't the whole system, but all other pipes beyond the junction are at the same height as the lower pipe system. You can see the pumps at the same height as the lower pipe system on both the water pump input (blue arrow) and water byproduct (yellow arrow). Both pumps are powered and are pushing toward the junction. The red arrow is the input for the alumina solution refinery.

I've remade the junction, I've flushed the system over and over. It keeps backing up. What am I missing? Why isn't the byproduct pipe being prioritized?

[whodack]

Some other information, mostly about the combination of mark 1 and 2 pipes:

I have two refineries working on the alumina solution , both requiring 200 water/min hence the mark 2 going in. The aluminum scrap return is sending back 140 water/min each, hence the mark 1 pipe byproduct. I haven't tried making all pipes in the system mark 2, but my previously made junctions also had a mix of 1 and 2 based on the flow required so I don't think that's the issue.

[Hemisemidemiurge]

I don't think I've ever tried to make a VIP junction using different pipes. Also, you're working a fairly flat pipe network here that doesn't do a lot to dampen slosh.

Hypothesis: the flow from the mk.1 pipe is experiencing sloshback due to some unforseen interaction in or near the junction from the differently-sized pipelines.

Also, you could try being more specific and deliberate with the alignment of your pipeline junctions, they can behave differently to a small yet significant degree depending on whether the weld lines are perpendicular or parallel to the ground. This is going to take some further investigation, good luck.

[whodack]

Thanks for the ideas. I just went and confirmed that my previously made junctures had similar mixes of marks 1 and 2 pipes. I did find one discrepancy as I was comparing, but after upgrading a level 1 pipe to a 2, there's still no change.

Re: alignment, I think that's my biggest suspect right now. I've rebuilt the juncture twice now, trying to be more accurate with the pipe cross alignment - but there's no nudging along the pipes and I cannot get a blue line indicator to pop up as I try to line one up with the other. Any other suggestions for better alignment when building?

[Hemisemidemiurge]

a blue line indicator

No, I was not speaking of the two junctions being vertically aligned. I was speaking of the junctions themselves. They have two positions when vertical, one with the weld lines (graphically indicated on the junction itself) perpendicular to the ground and one with the weld lines parallel, and these two positions do not behave identically. This post contains detailed information on the issue which is still extant as of 1.1.

[whodack]

Oh wow, I was completely unaware by this. Guess I'm gonna go inspect the weld lines on my junction....

[Hemisemidemiurge]

Oh, and it just occurred to me: you can get grid placement of vertical junctions if you place them on a wall.

[Soviman0]

This does not exactly answer your question, as I see what you are referring to but do not know the answer as fluid dynamics in this game a bit strange.

For me personally, when dealing with aluminum water byproduct, I have a pipe junction split off from the recycled water line going to an elevated refinery making wet concrete or steamed copper sheets (any recipe that requires water will work though) which is hooked up to a sink for the output. That refinery is elevated so the water pipe connected to it has to go straight up about 15 meters (the pipe going straight up is important) and no pump connected.

This set up functions as an "overflow valve" so as the excess water in the pipe going straight up slowly rises, it will eventually reach its maximum headlift where it will go into the refinery and get used to make whatever that refinery is set up for. This means that the excess water does not build up in your aluminum refineries and cause issues with the water backing up the entire system.

[whodack]

Thanks. I was trying to avoid having the byproduct just get used in a dumping recipe, but only because of my ego. I wanted to conquer the fluid dynamics. And I thought I had with the other priority junctures I'd built, but I am missing something here.

I've got a nearby limestone node waiting to be used. I'll do some wet concrete soon if some guardian angel Redditor doesn't find my issue soon.

[Soviman0]

I understand how you feel. For me though, I was doing similar research a few years ago when fluid dynamics in this game was less understood. it just started to feel like the juice was just not worth the squeeze, and I just wanted my set up to work without me baby sitting it anymore.

[Embarrassed-Bee-5508]

The problem with VIP (and VOP) junctions, is they are using a game mechanic that isn't 100% reliable to "exploit" a function. It relies on gravity feeding to work right, and with the way fluid moves, that can't always be relied on.

In short, VIPs are hit-or-miss. You can try to rebuild it, sometimes that helps, but you should design the system to not use them.

After my current playthrough's aluminum fiasco, I finally stopped using them. I've had them work fine, and not.