HEAT PUMP TYPE WATER HEATER

摘要

A compressor (25), a water heat exchanger (26) for raising the temperature of warm water, an electric expansion valve (27), and an air heat exchanger (28) are connected sequentially in the given order. A defrost circuit (38) is provided which supplies the air heat exchanger (28) with hot gas from the compressor (25). A defrost operation is started so that the air heat exchanger (28) is provided with hot gas from the compressor (25) and the electric expansion valve (27) is closed to a predetermined valve opening after an elapse of a predetermined length of time since the start of the defrost operation. <IMAGE>