I have a loose pipe that we cannot get to, it is behind a wall. It bangs loudly after any tap/toilet/water appliance is turned off/flushed etc. We put a water hammer arrestor by the washine machine, but it didn't really work as it happens with any faucet in the house.
I would appreciate some advice on how to stop it, since getting to the loose pipe isn't an option. Should water hammer arrestors be within 6ft of the problematic pipe?