Last experimental 0.17.47, also present in last stable version 0.16.51.

Attach a save file done with the last version.

Hi,

Setup to reproduce :
- One pumpjack
- One oil refinery (basic recipe)
- Two tanks, one for heavy oil and one for light oil
- Petroleum goes in a (short) pipe
- Three pumps connected at the end of the pipe, one in each free direction (e.g. north/south/east if the pipe comes from west ...