When multiple indoor units are connected to a heat recovery system, what must be true about their operation?

In a heat recovery system, when multiple indoor units are connected, it is essential that each unit operates in the same mode. This is because a heat recovery system is designed to reclaim heat energy that is being produced or absorbed by one unit and transfer it to another unit, enhancing overall system efficiency. If the indoor units operate in different modes (such as heating and cooling simultaneously), it can lead to system conflicts and inefficiencies, as the heat that is being extracted or ejected would not be transferable between units effectively. This unity in operation allows for optimal heat distribution and ensures that the system works harmoniously, maximizing energy savings and performance.

Options suggesting that the units can operate in different modes, must be of the same capacity, or must be located in the same room do not reflect the operational requirements of a heat recovery system, as the essence of such a system relies on the coordinated functioning of the units.