Gas Vents are overpressurized. Always.

Its a visual bug. The vents still working. (just the icon stuck there)

It's not a visual bug.
They are over pressurized.
They are working too though.
The reason is that they are toggling quickly between working and not.
So the icon just stays there.
This is because your pump and vent are in the same area.

They're like this whether you have a valve or not, and temperature doesn't change when pumping out 5C air. It's not a visual bug, they simply are not working. I don't know if they're not working because they are overpressurized or whether there's two bugs interacting, but I can say with certainty that something is very wrong with the vent functionality.

I can even have air going _into_ a vent and just disappear, again not changing the gas composition or temperature at the output.

The easiest testcase, build a vent and tightly wall around it. pump gas into that vent. When the small room gets saturated with air (every tile around 1000-1500g) it will be truly overpressured and the gas will be increasing in the vent storage and then in the pipe.

 

And the testcase for the visual bug, build a vent, disable it, pump 10kg gas in it, enable the vent.

Since it cant output the 10kg gas at the same time, it will get the overpressure icon but the vent will constantly output the air, and as the gas spread the vent can go down to empty easily. (you can turn off the pump) But since its a visualbug the icon will stay there even if the vent empty.

You seem to misunderstand. I'm well aware that the icon is bugged. The VENT stays overpressurized all the time. Does not exhaust air. Nada. Kaput. Pipes accumulate gas. No gas leaves. I can deconstruct at least back to the valve itself, rebuild and it gas still just reaccumulates in the pipes, 10g at a time.

 

It. Is. Busted.

Edited March 13, 2017 by JonathanSmith

If gas is backing up in the pipe, then there is simply too much pressure in the room and the vent can't vent.