While winterizing the fresh water systems yesterday I was bypassing my hot water tank when I noticed a valve (multi turn) where the hot water leaves the tank to the hot water manifold. This valve had both a hot water supply (from the tank) and a cold water supply. My guess is that it is a blending valve for hot and cold water to be used as a hot water temperature regulator. Does this sound right? My hot water has always been scolding hot so this may be a way to cool is down a bit.