Patent ID: 8584625

Claim:
A storage type water heater comprising: a stored hot water tank; a heating unit including a heat exchanger for heating stored hot water, a gas burner for heating the heat exchanger, and an air supply fan for supplying combustion air to the gas burner; a circulation pipe line for circulating the stored hot water between the stored hot water tank and the heating unit; a circulating pump provided on the circulation pipe line, for circulating the stored hot water in the circulation pipe line; a first temperature sensor provided on the circulation pipe line, for detecting an inlet side temperature T 1 of the stored hot water supplied from the stored hot water tank to the circulation pipe line; a second temperature sensor provided on the circulation pipe line, for detecting an outlet side temperature T 2 of the stored hot water heated in the heating unit; a flow sensor for detecting a flow amount of the stored hot water flowing inside of the circulation pipe line; and a controller, including: a first temperature monitor for monitoring the inlet side temperature T 1 detected by the first temperature sensor; a second temperature monitor for monitoring the outlet side temperature T 2 detected by the second temperature sensor; a temperature comparator for comparing the inlet side temperature T 1 detected by the first temperature sensor and the outlet side temperature T 2 detected by the second temperature sensor to calculate the temperature difference (|T 1 −T 2 |) therebetween; a sensor abnormality determining unit for determining the abnormality when the temperature difference (|T 1 −T 2 |) is greater than a predetermined value, and a notifying unit for sending a notification of the sensor abnormality in response to the sensor abnormality and performing an abnormality determination mode which actuates the circulating pump to circulate the stored hot water inside of the circulation pipe line when the heating unit is in a non-operated state, and determines the sensor abnormality in one of the first temperature sensor and the second temperature sensor based on a temperature different (|T 1 −T 2 |) between the inlet side temperature T 1 detected by the first temperature sensor and the outlet side temperature T 2 detected by the second temperature sensor; and an external operation device for presenting a notification about the sensor abnormality from at least one of a display and a speaker.