nicktheplumber
Dear doc,
I can’t explain your problem, especially your statement that the toilet that tees off the cold water supply (presumably before it goes to the inlet of the water heater) is filled with hot water. I was thinking that maybe your water heater had reversed inlet/outlet connections, or that your supply lines were plumbed backwards, but the basement toilet can’t be explained by either screw-up. Still, you might try reversing the connections to the water heater…
NtP
