In my expierence repairing frozen pipes over the decades, unless you temper the heat around the pipes, they will freeze. Bundled pipes in foam at 10...
You do not need a PRV at the meter, but if the building is actually 150 below the meter, then you will have about 150 psi at the building which means...
C is the vent for the tub, and the pipe extending horizontally is the trap arm before the p-trap is glued on. We always install the trap "after" the...
YOr picture is too poor for us to tell anything about pipe "C", other than if it is connected to any of the drain lines it points to, without a turn,...