Dan Listermann wrote:
Our cold water faucets always produce an initial stream of hot water
before the cold starts. I believe it has to do with the expansion
tank on the heater. There is a check valve on the water line that
feeds the heater, but the backflow seems to indicate that it does not
work. It is the flapper type and it is pointed down. Is there a
problem with trying to use this sort of check valve in a downward
position? I checked the arrow marking and it appears to be installed
in the right direction.

Heh! My water pipes go through the attic.

Yesterday, the attic's temperature reached 134°F (even though it was a balmy
104° outside).