A bypass valve is for support between hot and cold water lines that connect to respective hot and cold fixtures. The bypass valve includes a valve body having an internal chamber, a hot water inlet port, a hot water outlet port and a discharge port; a bi-metal spring; a support member for mounting the bi-metal spring within the internal chamber of the valve body; and a shuttle mounted to the bi-metal spring and constructed and arranged to mate with the discharge port in a closed position of the bi-metal spring. The bi-metal spring assumes an open position to disengage from the discharge port at a predetermined water temperature to enable the hot water to discharge through the discharge port to the cold water line.