water hammer????

I have a leaky upstairs shower head. Today I wanted to work on the leak, so I shut off the well pump and tried to drain my pressure tank by turning on the shower. The pressure was winding down, but then I started to get very loud water hammering. Am I doing something wrong? It sounded like it may be coming from the hot water tank??? How can I turn the water supply off to the shower so I can work on it???

Thanks,
NickyG

You mean there isn't a shutoff between the pressure tank and the house? I'm sure a real expert will have a better comment, but I've found that I get really strange noises when I drain the pressure tank, as the bladder inflates. Since the water heater is ideally the first thing the incoming water hits, any bladder-tank noises would be heard there.

Be sure and turn the WH off if you're going to shut off the water.

more help please

need more help please..... Are these noises okay?? Will they happen regardless of how I drain the lines. Will they damage the plumbing throughout the house. I will try closing the valve after the pressure tank and see if that works better to cut off water to the shower on my next attempt..

thanks