Even at priority 9, petroleum refineries still not being operated

Can you post a screenshot of your setup, with the plumbing overlay displaying?

Typically the issue is the plumbing from the oil refinery is poorly set up. A duplicant will only operate the refinery when there is room in the output pipe for the petroleum to go into, so if you have it plumbed directly into a petroleum generator or polymer press, they will stop as soon as the pipe is full.

To keep this from happening, plumb your refinery into a petroleum pool, with a second pump to supply the needs of the generator or press. Another way is to have a really long, winding pipe, but that gets messy.

That is how I have things set up, so it is possible that's the problem, but even then, it doesn't look like the piping is overfilling.

Part of your problem is you have the output of your refineries connected to each other. The problem with that is only one of the refineries can be used at a time, since the output of the other refinery is filling the pipe. If a duplicant attempts to use the second refinery while the other is in use, both will overflow the pipe, and interrupting the task. I'd recommend building a "backbone" pipe that both refineries output into, thus avoiding the feeding outputs into each other.

Same concept with the inputs of the petroleum generators, have them all fed off a "backbone" pipe, instead of connecting inputs directly into each other.

If you can post your save file, it'll help the devs in case there actually is a bug going on.

Edited April 6, 2018 by crypticorb

I have updated my setup a little taking into account your advice, and am still getting the same problem, so have attached the save file.

The Delicate Sewer.sav

I loaded up your save file, and checked out everything. I reworked your plumbing for the refineries and generators, and captured a point with both duplicants operating each refinery. Part of the problem is you need one pump per refinery, supplying 10kg/s of oil to each. Two refineries should theoretically be able to supply three petroleum generators, but unless you lock a duplicant in there 24/7 to crank out petroleum, try dropping it down to 1-2 generators until you get a good cache of petroleum.

This is off topic, but you seem to have a CO2 buildup problem, and slimelung on everybody. Try deploying a single CO2 scrubber, and use hand washing stations at the exits, and that'll clear right up. Good luck!

15 hours ago, crypticorb said:

This is off topic, but you seem to have a CO2 buildup problem, and slimelung on everybody. Try deploying a single CO2 scrubber, and use hand washing stations at the exits, and that'll clear right up. Good luck!

What I really have is a water problem. I have a couple of CO2 scrubbers but I've had a hard time getting enough water to them to keep them going. Similarly, I had sinks around the most disease-prone of my exits, but they weren't being used cause they weren't getting any water. At least part of the water problem is because I have the water supply running through two thermal aquatuners to reduce overheating, but they only run intermittently because of not having enough power.