My original heat pump was a combination unit. It made DHW on demand, so I have no experience with a desuperheater. The replacement unit is a water to air with desuperheater. I have looked at and shared Bergy's drawing many times. The main question I have is; When the DSH pump is running and the water is coming up the dip tube/cold water inlet, When it gets to the "T", Why doesn't the cold water, which is entering the "T" with household pressure behind it, dilute the recirculating water?