I have hot water heat, and my question is about a radiator in my attic. The radiator is currently shut off in the basement, both from the feed and return, with a quarter turn valve (the radiator does not have an adjustable valve on it). If I open both of the valves to the radiator will this add air to my heating line? If so, how do I prevent this? I personally do not have the "know-how" to bleed my system seeing as I am a first time home-buyer.