| 摘要 |
PROBLEM TO BE SOLVED: To provide a highly reliable heat pump type water heater capable of preventing the fatigue breakdown of an air heat exchanger even if the temperature rise operation of water and the defrosting operation of the air heat exchanger are repeatedly performed.SOLUTION: A heat pump type water heater configured to be at least switchable between temperature rise operation and defrosting operation, the heat pump type water heater comprises: a main circuit during the temperature rise operation, having a compressor 1, a flow passage selector valve 2, a water heat exchanger 3 exchanging heat between water and coolant, a first flow regulating valve 4, and an air heat exchanger 5 exchanging heat between air and coolant, which are sequentially connected; and a by-pass circuit 6 having a by-pass piping connected on the suction side of the compressor 1 for by-passing liquid coolant or two-phase coolant on the suction side of the compressor 1 and a second flow regulating valve 7 provided in the by-pass piping, in which during the temperature rise operation, the temperature of water supplied to the water heat exchanger 3 is detected, and during the defrosting operation, when the water temperature is a reference water temperature or higher, the opening of the second flow regulating valve 7 is increased from a reference opening. |
