The total zone heating load vs. total zone cooling load is used to determine the operating mode as either cooling or heating. In other words, the greater load---heating vs. cooling---presented by all indoor units on the system will determine the outdoor unit mode for the current simulation time step.
When there are simultaneous heating and cooling loads for indoor units on the system, heat recovery will transfer heat rejected by indoor units operating in cooling to those indoor units operating in heating mode, thus offsetting some heating load. This is always true, unless prevented via the Profile control option.
