Why does the PVC drain pipe in my wall knock whenever draining hot water?
Trust me, it's not the copper. It only does it when things are draining. Like, when the dishwasher drains it's hot water. Or, if I fill a sink with hot water, and then pull the plug. A little while after the drain begins to have hot water flow down it... it begins to knock inside the wall. I have a general idea of where it is. Any idea why this would be happening, what he dangers of letting it go on, and if there is an easy fix for it?
I have only owned the house since November, and it has done it ever since we owned it. I know about expanding copper, and water hammer. Trust me, this is not that.