Agreed.

I should have further specified that my chart is applicable for R410a units that are water-to-air.  I don't have familiarity with water-to-water units, and thus don't know if the R410a refrigerant temps are different.

For an R410a unit in heating mode, for a water-to-air unit, refrigerant temp going in to the DSH will be about 150 - 160 degrees, as shown on the chart I published earlier (red line).  (You can ignore the early heating seasom mode values that appear, that go up to 180 degrees - this was before a problem evap coil was replaced that caused a lowered refrigerant charge level, resulting in elevated refrigerant temp.)

Best regards,

Bill