Hi. For a while I had clicking noises coming from the pipework that sounded as if it was coming from upstairs. I have recently decorated upstairs and while I had a small section of floorboard up I noticed that some of the pipes running across a joist were loose so I pinned them down and two in one of the bedrooms supplying the radiator in there were as loose, so they too were pinned down. I used the plastic pipe clamps to secure them, but the noise is still there. I have subsequently replaced two of the upstairs radiators, flushed the system with a system cleaner, drained the system down again, added an inhibitor, refilled and bled the system and still the noise is there, albeit not as bad as before. My boiler is a Worcester combination CDI around 16 years old and has been serviced, although not every year. Can anyone offer any advice as regard to why the pipes are clicking and a cure? Thanks!