Previously, I had water hammer when shutting off shower, washing machine, etc. I installed an arrestor midway between the main supply and branches. Now I have hammer (a double shudder) when I turn any faucet/fixture on or off. The arrestor absorbs the pressure wave when turning off a fixture, but does the piston in the chamber within the arrestor then release when flow begins causing the shudder? I am about to remove the arrestor and see if it goes away.