I can't believe it's been a month since my last plumbing post. I've really accomplished a lot since then.
I did the shut-offs as I said I would, and consequently we have had hot water to Mary's sink and the tub ever since. My own kitchen sink decided to supply only cold water, totally unreasonably. So I turned off the cold to it and had only hot for two or three weeks. When I turned it back on, both the hot and the cold mysteriously behaved.
Eventually, I extended the usable line, installing stop valves for the bathroom sink, the washer, and the attic, and then got the washer hooked up (\o/ YAY for actually *clean* clothes), then the bathroom sink.
The water was too hot, and didn't come out very fast from some taps. There were faucets I took apart to clean out the bits of plastic I had missed that washed through the pipes when the water was turned on. I adjusted the water heater, turning the volume all the way up (against instructions) and the gas volume down, and low and behold, we have nicely hot water flowing at a reasonable rate out of all orifices that it is supposed to.
I've *never* gotten hot water to the bathroom sink so quickly.
And today I extended the line up to the attic. I actually haven't tested it yet, but Raederle theoretically has hot water to her sink. And to her toilet until I fix the cold water line. And one more stop valve for extending to the tub.
Now about the three *tiny* leaks ...