Make water and steam behave similarly to early 0.15 experimental releases. Water and steam are the same fluid (H2O), with varying temperature for different uses.

The icon and name don't change depending on temperature, the fluid is always called H2O with combo water/steam icon.

Gallery images description
1st image: H2O icon.
2nd image: Coal liquefaction recipe with steam replaced by H2O with minimum temperature requirement.
3rd image: Combined coal/nuclear power generation with pre-boiler. First coal boiler heats H2O to 165 degrees, then heat exchanger heats to 500 degrees.
4th image: Stretching nuclear steam by diluting with water. 1 part 500 degree H2O from the heat exchanger is mixed with 2 parts 15 degree H2O from water pump. Final H2O temperature is 177 degrees, which is still enough for coal liquefaction.

Note that internally this mod replaces steam with water and adds temperature requirements. Adding then removing this mod from an existing save will replace all steam with water, so be prepared to do some pipe cleaning if you're just testing the mod.