Abstract: In a hybrid water heater, a heat pump unit and a combustion heating unit are combined for heating water to be stored in a hot water tank. The combustion heating unit includes a combustor for heating water in a chamber by combustion operation. The chamber of the combustion heating unit communicates with the hot water tank through a first water port provided at an upper side of the hot water tank and a second water port provided at a lower side of the hot water tank, so that hot water heated in the chamber flows into the upper side in the hot water tank through the first water port, by using natural convection. Further, water in the hot water tank at the lower side flows from the second water port into the chamber.

Abstract: In a hybrid water heater, a heat pump unit and a combustion heating unit are combined for heating water to be stored in a hot water tank. The combustion heating unit includes a combustor for heating water in a chamber by combustion operation. The chamber of the combustion heating unit communicates with the hot water tank through a first water port provided at an upper side of the hot water tank and a second water port provided at a lower side of the hot water tank, so that hot water heated in the chamber flows into the upper side in the hot water tank through the first water port, by using natural convection. Further, water in the hot water tank at the lower side flows from the second water port into the chamber.

Abstract: The period of pre-purging is selectively determined for improving the utility. When a main run switch is turned on, it is examined at S1 whether or not the temperature of the oil in a frypot measured with a thermal sensor is not higher than a first setting level. If the oil temperature is not higher than the first setting level, it is examined at S2 whether the post-combustion time exceeds 10 minutes or not. When the post-combustion time exceeds 10 minutes, the pre-purging is carried out at S3 for 80 seconds. When not, the pre-purging is performed at S4 for 5 seconds. Then, the combustion is commenced at S5.