This is one of those problems that are not dealt with seriously enough by the building officials in really cold regions. I have opened a blog space at the bottom of this article for you to add in your case history so we can demonstrate that this is a large and continuing problem. Take a look...
Controlling a hydronic radiator when there is no water shut-off valve.
Hydronic heating means heating with hot water or steam. With older systems it often means overheating as well!
IS THERE NOTHING YOU CAN DO?
Hydronic heating was what kept houses hot a long time ago, and some of the old...