I've replaced several valves (standard shutoff) over the years, the ones you turn several times, to open/close. There may be proper name for them, but I do not know.
It seems to be hit/miss proposition for me. Some of them leak at the shaft, after installing.
I suspect the reason is that the rubber gasket gets cooked during the heating process. Many valves have a rubber parts in two places, one where they close the flow and another around the shaft.
How do you guys manage to get the valve installed without overheating the rubber parts inside? Any tricks?