Adaptive gas water heater, system thereof and method for automatically judging gas types

The invention discloses a forced blasting type adaptive gas water heater system and a method for automatically judging gas types for the forced blasting type adaptive gas water heater system. The method is characterized by including steps of starting a water heater by the aid of gas with a relatively low heat value at first, receiving data of inlet water temperature T1, outlet water temperature T2 and water flow m by the aid of a master controller, computing a heat load value QS according to a formula of Q=Cm(T2-T1), comparing a computation result with a heat load value QI of a theory of the gas and judging the computation result; and determining the type of the current gas, then switching to a control program corresponding to the gas, regulating current of a gas proportional valve and rotation speed of a fan, and accordingly realizing automatically identifying the type of the gas by the aid of a program. The data are fed back by a sensor module, and the heat load value QS is actually generated by the current gas. A traditional gas type selecting mode realized by means of dialing is replaced, a user does not need to know the type of used gas or manually set types of gas, and the forced blasting type adaptive gas water heater system is convenient in use.