The invention discloses a water-cooled full-premixing gas
water heater. The water-cooled full-premixing gas
water heater comprises a main
heat exchanger, a cylindrical heat exchange coil
pipe, a burner, a fume collecting hood and a main controller. The main
heat exchanger is arranged on the upper portion of the cylindrical heat exchange coil
pipe. The water-cooled full-premixing gas
water heater further comprises a draught fan and a gas
proportional valve. A
gas mixing pipe is arranged at a gas inlet in a bottom plate of a burner base. The gas inlet end of the gas
proportional valve is communicated with a gas source. The gas outlet end of the gas
proportional valve is communicated with a radial gas inlet of the
gas mixing pipe. The air outlet end of the draught fan is communicated with the axial lower end of the
gas mixing pipe. A preheating
heat exchanger is communicated with the heat exchange coil pipe and also communicated with a
water source. By the adoption of the structure, cold water is preheated in the water-cooled burner through the preheating heat exchanger,
heat energy is fully utilized on one hand, and it is guaranteed that flames are stable on the other hand; the cold water preheated through the preheating heat exchanger then enters the main heat exchanger,
heat energy is fully utilized, and the purpose of saving energy is realized. Through the arrangement of the draught fan, it is guaranteed that primary air is sufficient, the primary air and
fuel gas are fully premixed, the
fuel gas is fully burnt, and energy is saved.