knocking of steam radiator Home › Forums › Public Forums › General Plumbing › knocking of steam radiator This topic has 1 reply, 2 voices, and was last updated 21 years, 6 months ago by Harold Kestenholz. Viewing 1 reply thread Author Posts 25 Oct 2002 at 2:06 pm #275903 MasterPlumbersKeymaster My radiator has a very loud knocking sound when it starts to heat up. it only happens at night. it’s a one pipe system what should i do? 25 Oct 2002 at 3:27 pm #293102 Harold KestenholzParticipant Read the Steam Tips at: http://64.226.150.132/hydronic/steam/steam1.htm Author Posts Viewing 1 reply thread You must be logged in to reply to this topic. Log In Username: Password: Keep me signed in Log In