Banging pipe in shower

I have a handheld shower head. When I turn on the hot water in the shower, the hose bounces in the holder, and the pipes make a thumping sound. This only happens with the shower faucet- not with the tub faucet or any other faucet in the house. It also only happens when the dial is turned to hot. (There's one dial in the center above the tub faucet that you turn from cold to warm to hot. It also has a temperature monitor to protect against scalding.) I thought it might be the diverter in the tub faucet- the thing you pull up to by-pass the tub faucet and send the water up to the shower- because it was leaking water out of the faucet while in shower mode. I replaced the faucet, so it no longer leaks when in shower mode. I also opened all known water valves to full. That made it better, but it hasn't stopped. Also, the shower pipe can be moved in and out of the wall- like when you put the shower head back up to the holder. Could it just be my handheld needing to be replaced- like it's in vibrating mode permanently or something? Or that the pipe's not secure in the wall? Help! I'm clueless. I know I probably have hammer thingy, too, because the toilet makes a thump when it finishes filling- although that's not as loud anymore either. What to do?

It sounds like you have excessively high water pressure. If you go to Lowe's or HD you can purchase a water pressure gauge and attach it onto your outdoor hose bib and with all the water turned off in the house & turning on the hose bib you can check to see what your water pressure is. Then you will know if excessively high water pressure is your problem. If it is, then you will need to have installed a pressure reducing valve and an expansion tank & set the air pressure in the expansion tank to match whatever, you set your water pressure at.

Thanks for the response, Cookie. Would only the hot water in the shower have an issue if the water pressure was high? No other faucets in the house have that problem. Thanks again.

First you say it only happens when you turn on the hot to the shower, (and refer to the shower faucet only), but not to the tub, inplying separate faucets, but then you refer to a diverter spout, which implies a single faucet. If it is a single faucet how do you turn on the water to the shower without turning it on to the tub first and then operating the diverter spout.

Sorry for the confusion. I'm not great with descriptions and don't know the real terms for things. What I have is what you described better...My tub/ shower has one real faucet. There is a little tab-like thing that you pull up to make the water come out of the shower head instead of the faucet. So it is as you said- you turn on the faucet so the water goes into the tub, and then you pull up the diverter thing so it comes out of the shower head. The banging/ thumping/ knocking only happens when the water is turned to hot, and only when the shower is on. It doesn't happen when the faucet is on hot for tub.

It sounds like you may have some debris caught in the shower riser (the pipe going to the showerhead) or the shower arm (feeding the shower head that comes out of the wall). When the water is on, it vibrates. You might just try taking the showerhead off, and turning the water on to see if it gets flushed out. Take a close look at the showerhead, and thump it a few times to see if you can get anything out of it. If the water flows freely without noises, it may just be the showerhead. If not, you've at least narrowed it down a bit.

Thanks, Jadnashua! I took the shower massage down, ran it, shook it, and tons of debris came out. I then undid the shower massage hose and head thing from the shower bracket (the thing that looks like a ball and socket- sorry for my lack of knowledge of parts) and ran the shower w/o the hose and head. The water seemed to pulse when it came out without a shower head. The water was running only through the bracket, but that piece is came with the shower massage, so I don't know if it would pulse without that, too. I'm going to get a new shower head and connecting joint/bracket and see if that does it. Thanks to everyone for the tips. This is so cool- people reaching out and helping!