Hi - recently moved into an old house. When we first moved in we could hear a bad water hammer (clanging) on the pipes upstairs whenever we turned off the taps on the sink downstairs - it was louder the quicker you turned off the taps - it didn't occur anywhere else. However, we had a combi boiler fitted soon after, and this seemed to co-incide with the problem disappearing. It has all been quiet for a year - until now. We have just replaced the bathroom suite. Now when turning off any of the new taps on the shower (lever type), bath (1/4 turn), sink, flushing the toilet (when it finishes refilling) and when using the washing machine, the water hammer is back with avengance. We have secured the pipework with clips in the bathroom floor, and, to the extent that is possible, under the boards upstairs in the hallway. The clanging is so bad that we could even feel the pipework move right back to the front door by the stopcock where it enters the house. So, my question(s). I've read a bit about Water Hammer (shock) Arrestors 1 - Can they be fitted with a combi boiler system? 2 - Can anyone recommend one? - might this work for example http://www.plumbcenter.co.uk/en/rwc-1-2-water-shock-arrestor-82361?top_category=18233 I have also read that changing the main stop cock to a lever type can help - why would this be? Thanks in advance for your help!