Lound Banging Noise with sngle handle shower valve!!!

We are having a new addition put on our house and everything should be wrapped up in the next two weeks.

When the single handle shower valve is in the six o-clock position (warm) the water pipes chatter loudly (loud banging sound), if the handle is moved slightly (hotter or colder) the noises stop.

The shower wall is tiled and it’s an American standard fixture set.

I called the plumber who installed everything last night, and they are sending someone out today. Does anyone have and idea what that might be? Loose pipe? Loose valve?

I’d like to have an idea in mind when I hear back from them later today…

Thanks!

Water Hammer

It sounds like "Water Hammer" where air gets trapped in the pipes. Try opening the valve all the way and run the water for a few minutes....see if that helps.

Water hammer occurs when you have a fast acting valve and you shut it off. The intertia of the water column tries to keep moving, and anything that is loose moves (think hitting a brick wall in the car). This causes the pipe to bang into something. You could have a loose washer or something in the valve that is restricting the flow; maybe in a shutoff valve.

It may be something in the pipe, or the cartridge.

Last week, I pulled a plastic ball out of the incoming 1/2" copper pipe.