I'm having trouble getting the overflow valve from @AndreAquila's Fluid Sink and More mod to work. It seems to just stay open and let whatever system pressure is available through. I can't find any guides, or answered questions online about how the valve itself works, or any instructions on how to use it aside from what seems to be self explanatory. Attached is a pic of how I have it set up. None of the pipes, machines, or storage buffer are full. The only thing I can think of is that I use the All Fluids Are Gasses mod by Kyrium, which might be interfering with it's operation.