: I recently remodeled my hallway bathroom, which consisted of removing the old cast iron tub and replacing it with a walk in shower. I extended the supply lines for the new Moen shower faucet about two feet laterally, and two feet vertically, and then extended the line that feeds the shower head about six feet. I also split that line at the end with a tee to provide for two shower heads. After a couple days of use with no incidents, a loud and forceful jack hammer sound is produced when the shower is turned on. Sometimes it will happen when the water is already running. However it starts, it can always be silenced by adjusting the shower faucet and will then run without incident. I have noticed that the hot water heater has been making more noises also. The master bedroom shower has a similiar problem but with out the noise and force. That shower has two seperate faucets and the side that pulses is a detachable shower head with flex piping. Any idea what's going on?
Remove the shower heads and see if it still makes the hammering sound. There could be a problem within the shower head(s) or a loose part inside the faucet or diverter. The piping changes that you made wouldn't cause this problem.
As for the WH noise, there's no telling from here.
Good Luck. e-plumber