I have only recently had a problem with water hammer within my pipes at home, i have changed the ball cock valve for the cold storage tank, and drained down the system, from the radiators, in the house. but still i cannot solve this banging. And sounds as if it is coming from within the walls of the House, i think there is air trapped in the system somewhere, and would stop, when i turn the mains water off. But do not know a solution, which is why i want to learn more, about this problem can you offer any advice ?