Experimenting with atmos, I found a fundamental difference in both gas pumps and volume pumps. One pumps to a specific pressure, the other pumps out gas at a rate, which happens to be liters per second, so a volume pump should be constantly pumping out gas until there is 0 liters in the input end.
Strangely enough, it doesn't seem to matter what setting you put on the volume pump, it will pump at exactly the same speed. I created a test where an input canister would be connected to an output canister with a volume pump, the input canister being filled with air. I placed two of these tests next to each other, then I configured their volume pump settings. One would be at 200 L/s, the other at 10 L/s. When both volume pumps were activated simultaneously, they managed to fill up their respective output canisters to the brim at the same time. If it took 10 seconds for a 200 L/s volume pump to fully fill a canister, shouldn't it take 200 seconds for the other one?
Even weirder, you can set volume pumps at 0 L/s and it works all the same. This is unintuitive to me, because how can a volume pump pump out 0 liters of gas every second and still work?
In any case, I probably just don't know anything about how atmos works, but it's weird that the settings don't seem to change anything, I would think that they would work at different speeds. Maybe the test I did was too small or something.
I really don't know, I'm no atmos tech (or coder), but I would like to know.