Gas water heaters generally include: casing, supply and exhaust devices, burners, heat exchangers (commonly known as water tanks), gas control devices, water control devices, water gas linkage devices, and electronic control systems. The specific structural components mainly include the shell, surface shell, switch knob, smoke pipe (strong smoke exhaust pipe), fan motor (optional), air pressure switch, heat exchanger, temperature controller, burner, water gas linkage valve, electromagnetic valve, exhaust hood, ignition machine, ion flame sensing needle, pulse generator, bottom shell fixing plate, electric controller, bottom shell, etc.