Often temperature of output coolant after refining metal in Metal Refinery is not calculated correctly.
On my PC this happens about 20% times. Here in this save are 10 refineries and 10 duplicants making iron. Input is freezing 0C water and buildings are same and bellow 10C. Output water temperature should be 32-33C. (as it is after first refine)
Sometimes instead of "averaging" output temperature it is somehow added together with current temperature (even if current mass is 0kg). So if that happens output water is 65+C. (also sometimes it is 0C instead of 32C)
If I am "lucky" it can happen 2 times and then output is 98+C and sometimes when it happens 3x water can get to 130C and pipe break. (as at the end of the video)
Load save and monitor output water temperature.