I "bleed" the radiators to ensure that the system will operate properly every two year. I opened the water valve to allow more pressure into the system than I would turn on the valve in each room to make sure there aren't any "airlocks". Every room is fine but one. The water in that room is cold that means there aren't any airlocks... I can't seem to understand why this is happening. If you have any suggestions, please let me know.