Advice on Replace Radiator and Both Valves

[Jo-jo]

Hi, we are replacing one radiator and both valves, I’ve watched a few how to videos and everything makes sense about draining and re filling the system, I’m just unsure what you do with the valves on all the other radiators that your not working on, do you turn them on or off? sorry if it’s a silly question I just can’t find any mention of this. Thanks in advance Joanne

[collectors]

Make sure they are all open as it will flush out the system of muck at the same time. Also when filling back up, add some rad inhibitor.
https://www.youtube.com/watch?v=9XRQJ4Ge49I