Abstract: A heat exchanger includes a plurality of heat exchange units each including a plurality of flat tubes, a plurality of fins, an upper header, and a lower header. In the plurality of heat exchange units, the upper headers are connected such that the upper headers communicate with each other, and the lower headers are connected such that the lower headers communicate with each other through an opening-closing valve. The heat exchanger has a configuration in which when the heat exchanger serves as a condenser, the opening-closing valve is controlled such that refrigerant in at least one of the plurality of heat exchange units flows in an upward direction, and refrigerant in the other one or the other ones of the plurality of heat exchange units flows in a downward direction.

Abstract: An outdoor unit includes a housing, a heat exchanger provided inside the housing to exchange heat between refrigerant and a heat medium, and a valve provided inside the housing and connected to the heat exchanger by a pipe, in which a lower end of the heat exchanger is positioned above a connection unit configured to connect the valve and the pipe.

Abstract: The controller controls a bypass solenoid valve and hot-water supply expansion unit in a defrosting operation based on a refrigerant temperature detected by a first temperature sensor and a heat medium temperature detected by a second temperature sensor.

Abstract: The controller controls a bypass solenoid valve and hot-water supply expansion unit in a defrosting operation based on a refrigerant temperature detected by a first temperature sensor and a heat medium temperature detected by a second temperature sensor.