I'm completely unable to insert fluids into vats. This issue occurs even with only Create and Destroy enabled on Forge v47.2.17. Below are some images of an example setup, although it has occurred with every configuration I've tried:

1 bucket of fluid exactly is inserted into the vat wall block, and according to /data, the fluid transferred remains in the interface block's internal buffer. Fluid continues to flow visually through the pipes without transferring anything.

So far, I have tried:

• Speeding up/slowing down the pump
• Pumping air out of the vat
• Inputting from different sides
• Applying redstone signals [I was getting desperate lol]
• Using different casing materials

Item I/O seems to function correctly [as far as I could see]

latest.log

If it was water I had the same issue. You need to distill the water using bubble chambers before the cat will let you insert it

Ah okay, I just kinda presumed regular water would be permitted as I didn't think distilled would be necessary for everything water-related.

I can't do it now but I'll see if distilled water works next time I play.

If it was water I had the same issue. You need to distill the water using bubble chambers before the cat will let you insert it

Yes, the Vat can only hold Mixtures (fluids with the ID destroy:mixture). The ponder will probably be updated to reflect this, and if tutorials are implemented (#60) this will definitely be something mentioned.
There side of the Vat accepting water in its internal buffer is definitely a bug though, and that will get fixed in 0.3.

Ah, I never noticed that, thanks for the help in any case

Fixed in 0.3.

I still appear to be having this exact same issue in 0.5

Screenshots in order showing the process I did to confirm it was still accepting water.

Pumped it into vat, broke vat, remade vat, 1000mb gone