I have water hammer on my mains cold supply and it’s driving me mad. The hammer is noticeable where the supply enters the house in the cellar. The pipes have all been clipped. It is most noticeable when quick close valves shut such as the washer and the dishwasher. It was slightly noticeable when other taps were shut off before any changes made to the pipe work. I have tried draining the system and this alleviates it but as soon as all the upstairs taps are used and the air expelled then the issue returns. I have had the stop cock replaced and I asked my plumber to install a water hammer arrestor. This has been installed just after the stop cock and is a metal bell style expansion vessel. I have also installed a Sioux Chief mini restor on my cold water feed on the washer (as this was the main culprit) The issue is still present and actually seems worse. The pipes no longer shake violently but there is a loud thud that comes from the newly installed expansion vessel in the cellar and this causes slight movement of the pipes. This thud is quite loud and echoes throughout the house. This thud occurs when ANY tap is turned off now (unless turned off incredibly slowly). The mini restor has made no difference to the issue when the washer is filling as the noise is coming from the cellar. I’m a plumbing novice but it almost seems as though the vessel in the cellar can’t cope with the pressure and that’s what causes the loud thud. Any other suggestions. I’m totally tearing my hair out. Oh and I don’t have a water meter. Thanks.