One of the radiators has never worked

[Slim Denby]

A plumber said years ago that it had been installed with the plumbing backwards and the only fix involved would involve digging up the sitting room.
Can anyone shed some light on this?

 

[Deleted member 120897]

Would need more information. What type of system? how large is the system? It could have been piped up wrong and might be corrected elsewhere. Photos may also help us.