ELECTRIC HOT-WATER HEATER

摘要

PROBLEM TO BE SOLVED: To attain cost-down and the miniaturization of a device itself by miniaturizing a motor-driven pump to be used for various electric hot-water heaters by reducing the number of parts and to simplify an assembly process by mounting the pump on a printed wiring board. SOLUTION: A motor-driven pump 14 is composed of a coil 17 for generating a rotary magnetic field and an impeller 16 having a permanent magnet 19 and rotates the impeller 16 while receiving the rotary magnetic field. By arranging the coil 17 on a printed wiring board 24, the miniaturization of the motor- driven pump 14 and the simplification of the assembly process are enabled and safety can be provided as well by miniaturizing the device.