The Burner/Heat Stills from Heat Processing use underground connections for their fluid inputs, which are impossible to connect to with AUP.
Would it be possible to let AUP's pipe to grounds/underground pipes hook up somehow? Or is this something better requested on the other mod's side?

This is the right place for that request... I guess I never considered machines with non-aboveground connections. I should be able to handle those, I'll let you know if there's any compromises I have to make

Fixed for next release