I purchased a ground floor flat about a year ago. Recently my boiler pressure has been going down quite a lot and I have had to re-pressurise it at least once a week. I called a plumber over yesterday and I found him unhelpful and rude but he did say something that has sat on my mind. He said I need a condenser pipe on the outer building. I don't have one there and I'm not sure if mine is near the sink. He also said I need a safety vent pipe. I have the flute. I don't want to break any law but I'm quite confused and lost because no one has ever told me this. Any advice would be appreciated.