How do I locate my Main Valve in a Steam System?

coolfx35

I looked everywhere but cannot locate my Main Valve? could they be hidden inside a wall? I have a finished basement.

Thanks.

https://www.youtube.com/watch?v=xb2Q21KvV0Q

KC_Jones

There may not be a main vent, or someone took it out. And yes it's quite possibly someone did you the disservice of burying it inside a finished wall, in which case it's time to go hunting.