Guest
It seems rather odd to me that there are no ports to release air on your radiator did you look very close at the top or sides of the radiator there are not always large handles. Often they or very small about 1/4in requiring a special key to be able to turn them open. There should also be the same type of valves located on the top side of the heat pipes on 90degree elbows where the hot water tuns to go down to a lower floor or crawlspace or basement
