I've prepared my story for PUT ahead of time! Here it is:
I was re-doing the plumbing in my mother's basement bathroom this week. I needed to solder my pipe into the wall where I had removed the old plumbing. This is at the lowest point in the house. I had opened all the faucets in the house, but the water kept dripping even after two hours of waiting. Every time I tried to solder in to the existing pipes, I just kept getting steam and couldn't get it hot enough to melt the solder.
This was driving me crazy until I found a plumbing forum that discussed this. (I bet you guys already …