DC motor controller for water heater

The utility model relates to a controller for a direct current motor of a water heater, comprising a blower control system, a rotational speed detecting circuit and a microprocessing unit. The blower control system is provided with a direct current motor which is connected with three control circuits, wherein, a first control circuit which can eliminate the noise of an alternating current power supply is connected a third control circuit, the input terminal of the third control circuit is connected with a second control circuit and can control phase positions according to external signals, and the output terminal of the third control circuit is connected with the direct current motor. The rotational speed detecting circuit can be used for detecting the rotational speed of the direct current motor; the microprocessing unit can calculate information which is output by the rotational speed detecting circuit and can output control signals, so that the optimum rotational speed for the direct current motor can be obtained.