One kind of card-type electric water boilers and working methods

The present invention discloses an electric water boilers card and working methods, the present card electric water boilers comprising: the waste water tank, hot water tank, and a cold water tank connected to the hot water tank, the cold water tank wrapping peripheral outer bladder the waste water tank connected by a wastewater collection tank, and a first, a second drain passage, said first, respectively a first, a second solenoid valve on the second drain passage; the waste water tank There is also a temperature sensor; processor module acquires the detected temperature of the temperature sensor, controlling the first solenoid valve is opened, the cold water through the first drain pipe into the sewer; or opens the second solenoid valve, the second hot water drains into said outer bladder, to heat the cold water in the tank. By the method of the present invention can return some of the water, waste water was poured to encourage the user to the receiving tank, while the waste water to the cold water tank is heated by warmth.