[NiHaoMike]

Originally Posted by Ormston

For dhw heating the odr needs to be disabled as it would limit water temp.

For hydronic heating purposes the odr limits water temp to just hot enough to keep the house warm.
It saves energy due to the way refrigerant heat pumps power consumption is proportional to the output temp(and to a lesser extent the input temp). The higher the output temp the higher the power consumption.
My ASHP draws around 850w when heating my floor to 24C and 1300+w when heating my water tank to 50C.

Steve

An alternative is to add a thermostat to force the heat pump to run if the DHW tank is below a set limit. If you're on city water, the minimum DHW setpoint might be as low as 105F or so. You can also consider installing a desuperheater that will give very hot water (as high as 160F in some cases depending on system design) when the heat pump is running.