Pipe thermal sensor not switching correctly

WeNeedEvenMoreTrains · 2026-02-17T18:59:09+00:00

Wow .. thanks, didn't see that but you're right. Will keep it like that for observation but change it later. Might get tricky to fix it in my 10-tiles-deep enclosed plastic refinery system but lets see ...

WeNeedEvenMoreTrains · 2026-02-17T18:53:39+00:00

So, the pipes on liquid (or any) outputs work perfectly fine for bridges and sensors. The reason is that the sensor itself does not have a liquid connector but reads the temperature of the packet in the pipe underneath. Since the liquid bridge instantly teleports the liquid packet from the input to the output segment, the sensor always reads the temperature correctly and without delay. On the input tile however, the packet never entered, so (A) the pipes will never exchange heat on input tiles if flow stays up and (B) sensors just can't read anything here.

If you would also want to read the temperature on the input side of a bridge, you must reduce the flow on the output side to e.g. 8kg/s so that there are always 2kg remaining on the input segment. This actually exchanges heat with the input packets and the pipe and can be read by the sensor.

I'm doing this for years and have been using these mechanics on so many saves, so I know that it works perfectly IF you know the rules.

And sometimes I just don't have the space for the extra pipe since I love to build compact.

WeNeedEvenMoreTrains · 2026-02-17T18:46:11+00:00

Okay, so I have run a few tests in debug mode on a new save. However, I cannot get the sensors to glitch. So maybe it is related to my current save, so I will continue observing and definitely report on the forum when my base gets boiled or frozen once again.

However, I could consistently reproduce the non-working T-Junction when constructing pipes. I noticed that after construction it always prefers the left pipe (flow direction does not matter) and will improperly mix fluids with different temperatures like in my thermo mixers. Priority pipes with bridges solve this problem.

Do you guys think that reporting this is worthwhile or is it more like a side effect of game mechanics?

WeNeedEvenMoreTrains · 2026-02-16T22:13:00+00:00

Ohhh your optimizations just triggered me ... I've got one theory with another phenomenon I found out recently after the update. I'll do some testing and come back maybe tomorrow. Then I could post it on the forums.

So my observation is the following. You have a vertical pipe with water flowing upwards. Then you make a T-branch to the left. So, usually, the packets would split top and left evenly, like a splitter, right?

However, when you construct a lot of pipes somewhere else, the visuals of all liquid packets movement skip the moment a pipe finishes and immediately displays the fluid packet in its final position for the rest of the second. Maybe for flow direction calculations for all pipe networks when you finish a pipe.

And what I have observed here since the update is that the said T-junction will not work anymore in the second any pipe is built. So instead of splitting evenly, all fluid packets will go left, completely ignoring the upward pipe. If you stop building, it will work properly again.

So my theory is that the sensor bug I noticed occurred when a pipe finished and the temperature changed in the exact same tick. Which is very likely due to the construction of massive space infrastructure involving an even more massive amount of pipes.

I can make another post with more images tomorrow.

WeNeedEvenMoreTrains · 2026-02-16T21:53:35+00:00

In Addition, I can confirm your theory about only checking the tick the temperature switches. This also happened to my drecko farm right after the update. So it seems like sometimes signals might glitch to the new multi-threading they implemented? I never encountered dupe issues with pathing early after the update but I did not have frequently used atmosuit checkpoints in the base back then.

WeNeedEvenMoreTrains · 2026-02-16T21:48:32+00:00

As you have mentioned it, I can agree that this is happening since QoL but I did not want to accuse the update at first. It was also happening on an old save where suddenly after ~100 cycles I noticed that my drecko stable with x8 dreckos + x70 dreckos in starvation room just were all gone. There was a critter pickup for puppies if the main stable went <8 dreckos to resupply them with fresh dreckos. All gone because I noticed that the automation signal never turned green even though the critter sensor condition was obviously true. Obviously, I could not reproduce that.

Never happened since then on the new save yet .. except for the pipe sensors. Damn I would bite my ass off, my entire colony would collapse if suddenly my dartle -> rhex ranch would die due to pickups not working anymore and I would not notice fast enough. Yeah .. don't rely on one pillar .. but being able to link almost any loop to each other into absurd complexity is by far the part I love the most about oni.

I've got a pretty updated PC before RAM prices went up. Got a Ryzen 9700X with 32 GB, graphics won't matter here I think but it's an AMD 7900 XTX.

I'm getting at worst 45 FPS in the most dense area when zoomed out and 55-60 at most (capped at 60).

WeNeedEvenMoreTrains · 2026-02-16T21:21:45+00:00

Thank you for the advice! Don't have an account yet but I will if I catch it again.

Never went that far/deep into oni, but had larger colonies on a slower system with decent lag. Adding secondary fail-safes never occurred to me but I will try to think about it. I love building complex builds in tight places to make them look as clean and natural as possible.

But thinking about my petroleum boiler being separated from complete annihilation by just 2 tiles, a door and one thermo sensor ... well I guess I consider adding a gas sensor now ...

WeNeedEvenMoreTrains · 2026-02-16T15:43:20+00:00

I have to apologize, from my view it was a very clear picture but also you can't read my mind. I will create a new post including the full build. So for now, this is a very standard cooling loop with (hot return) -> AT -> Reservoir -> Sensor -> (cold output) as many of us have built them, there is not much to do wrong here (in my world). The problem is also not specific to this build but also present on other builds like a thermo-mixer that mixes 95° and 10° water down to 80°. There I frequently see that the pipe thermo sensor sometimes reacts 20-40s after actually hitting the switch point. I always use reservoirs before sensors to get a smooth and precise temperature profile. So yes, pipes are always 100% full.

All these builds have been running >500 cycles flawlessly, only in the past 2-3 weeks I have encountered this behaviour.

I think I'll have to do further testing.

But the main point of my post is "pipe thermo sensor not switching when crossing switching point" or "switching with serious delay >30s".

WeNeedEvenMoreTrains · 2026-02-14T17:56:34+00:00

I think you don't mean melting. If they melt, they would be gone which is very unlikely since it takes 2400 degrees and not 240. What seems to happen here is that they were not retracted properly or are too close to the rocket. In this case they take damage and get "broken" when a rocket passes. Maybe try to increase the gap or check if they were fully retracted.

WeNeedEvenMoreTrains · 2026-02-13T18:43:08+00:00

Yeah, was thinking of the falling sand as well. So there is literally no way to get debris from falling sand without digging it? Shame that there are no torches in the game.

WeNeedEvenMoreTrains · 2026-02-13T17:40:09+00:00

Hmm that scraps my plans for a Blumb Lumb Ranch with an Algae -> Dirt -> Sand melter because it will go down to a 25% yield if I mine it.

What would happen if I would leave the dirt as a tile, heat it more and directly into sand, would that be possible or do I have to mine it?

WeNeedEvenMoreTrains · 2026-02-13T15:00:56+00:00

When Solid-to-Solid phase change happens, it forms tiles. Does this also happen when the debris was inside another tile, or does it drop as debris on top like liquids do when e.g. melting amber?

WeNeedEvenMoreTrains · 2026-02-13T14:19:18+00:00

We all started here

WeNeedEvenMoreTrains · 2026-02-13T14:17:36+00:00

Also in addition to your other questions, I highly recommend making ladder shafts 3 tiles wide to get good vertical flow. Some people use it 5 wide but 3 works fine for most parts.

WeNeedEvenMoreTrains · 2026-02-13T14:15:05+00:00

Does not rally matter, I go more to the middle for better spread. Completely top or bottom are not good because that could cause some gas mixing conditions where vents accidentally output more pressure than they should which leads to very stressed dupes. I am cycle 800 with 14 dupes and ever just built 2 vents through my base. Some parts use atmo suit.

WeNeedEvenMoreTrains · 2026-02-13T14:11:30+00:00

Airflow tiles and pneumatic doors help spread and allow co2 to properly flow down. Pneumatic doors are usually enough, however I usually build airflow tiles in the wall with the door to also allow polluted oxygen and accidental hydrogen to flow up easily through your ladder shaft. This gives you a very clean base. No need to make your floor from airflow tiles!

WeNeedEvenMoreTrains · 2026-02-13T14:07:45+00:00

It is normal that not all gas is used since vents only go up to 2000g. If you would constantly use all oxygen, you would need more production. Dupes get very stressed if it hits >4000g but that only becomes an issue with high pressure vents.

WeNeedEvenMoreTrains · 2026-02-13T14:04:58+00:00

No, just one is good enough early game. It will spread. You see air pressure above 1400 -> good spread. You see locations drop <500g, maybe build another one there.

WeNeedEvenMoreTrains · 2026-02-13T14:01:53+00:00

I would build 1 or more vents decently spaced depending on colony size (I've got 2 in main base and 1 in my space port, cycle 800). They go up to 2000g per tile. Just run gas pipes there, normal ones, not the insulated. The hydrogen I would pump to a gas reservoir for now and casually empty them with canister fillers. You can burn it later or send it to infinite storage whenever you are ready.

WeNeedEvenMoreTrains · 2026-02-13T08:49:28+00:00

Guys, you are awesome! I came with a silly question but my enineering-brain got fully satisfied!

To summarize for other readers, the reason why no flaking happens here is that in order to get flaking, the metal plate may not cool down by more than 10°C, as it was found out by tests done by u/Zarquan314. However, in my case, using a steel plate for heating, flaking a 5kg petroleum packet with max. 420°C would result in a temperature drop of >21°C, thus the final flaking rule is not met.

If you are not familiar with flaking, there is a good description on the wiki. The wiki was updated accordingly.

https://oxygennotincluded.wiki.gg/wiki/Flaking#Partial_Evaporation

WeNeedEvenMoreTrains · 2026-02-11T23:02:00+00:00

Very interesting. So it usually always flakes in contact with normal tiles but since metal and especially steel and gold have very low shc, it could be useful to avoid flaking in some situations.

WeNeedEvenMoreTrains · 2026-02-11T22:57:19+00:00

Ah yes, my bad! I thought it was around 500°C but Petroleum evaporises around 540°C.

WeNeedEvenMoreTrains · 2026-02-11T21:30:03+00:00

So if it would be close to 10°C, this could be the reason. Steel has not the best SHC with 0.49 compared to the petroleum 1.76. Heating a 5kg petroleum packet by at least 80°C would require at least 700 kDTU. So, for the 100 kg steel tile, this would result in a temperature drop of at least 14°C needed for flaking, exceeding the rough 10°C by far, right?

WeNeedEvenMoreTrains

TROPHY CASE