We have had a radiator that requires bleeding every day for about 2-3 seconds. If it is left say over the weekend then it is considerably longer and will also go to the rad to the bedroom right of it. Up to now i have tried sludge remover, complete drain down and flush out, boiler silencer and new pump. Another issue whether related to this problem is CH will not work unless hot water and central heating are both on at the programmer. My initial thought is leak and to use leak sealer but lately heating not been on, so no pump running all is fine. Would that indicate no leak ? Hope someone can help please.