DougE wrote:
The Plastic Pipe Institute recommends that the temperature of continuous water flow in PVC pipe not exceed 150*F in non-pressure applications.
^This.
I don't make a habit of dumping boiling water without running some cold water with it.
In a pressure situation, I softened a sch 40 pvc pipe using it as a splice between the upper and lower radiator hose in a demo derby car. Of course the coolant was probably 250F and under about 15psi pressure. Dang pipe collapsed and came out of the hose clamps. Lost the race. Steel pipe next year!