I recently bought a three story, 90 year old house. It is heated with hot water radiator heat. The first and second floors have always had heat. Because the third floor is never used the radiators were shut off. I am having work done to improve this area for resale value but because the house is so large it will remain unused while we are here. I added a little water to the system to pick up the PSI some and opened the radiators to see if they work as well to give my work men warmth. All but one gets hot but I know that it is full of air. When my men are through working I don't want to heat this unused space. At night our temperatures have been below 5 degrees. I know that turning off the radiators will stop the heat but do I need to be concerned with pipes freezing and bursting now that they are full of water?

We have a forced hot water heating system with 3 zones. The last couple of days it's been below freezing. The first night our digital thermostat went which I replaced the next day. But, since then the baseboard heater in our bedroom is not working even though every other baseboard on that zone is working. We had a tech come out today and he said that most likely the pipe for that baseboard is frozen. My husband tried to bleed the baseboard today and immediately no air came out and water started to trickle out - so that seems right that there is no air in the baseboard. Does this seem right? Does anyone have any suggestions - the tech said to wait until the weekend when it is supposed to be around 50 and we can see if it starts running again... Thanks! Deena