Patent ID: 9249988
Filing Date: 2016-02-02
CPC Classification: F23N,F24H

Claim Text:
1. A water heater, comprising: a combustor; a gas valve provided on a gas pipe to control a gas supply to the combustor; a blower having a motor to provide air to the combustor; a detector directly sensing a speed of the motor of the blower; and an operating device having a calculating unit electrically connected to the detector, wherein the operating device is stored with reference speed ranges of the blower under various gas supplies to control the gas valve; wherein the reference speed range of the blower is between a low critical speed and a high critical speed of the motor of the blower; wherein the low critical speed is a minimum allowable speed of the motor for an aged blower, and is greater than zero; and an exhaust pipe to exhaust waste gas of the combustor, and the high critical speed is a maximum allowable speed of the motor before the exhaust pipe is jammed; wherein the operating device determines whether the blower is working normal or not based on the speed sensed by the detector which is sensed after a predetermined speed up time of the motor, and the operating device determines that the blower works normally when the sensed speed is within the reference range of the blower, and determines to control the gas valve to cut off the gas supply when the sensed speed is outside the reference speed range of the blower.