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.

The gas water heater is mainly composed of a valve body assembly, a main burner, a small fire burner, a heat exchanger, a safety device, etc. It also includes the flue of a flue water heater and the forced exhaust device of a forced exhaust water heater. The valve body assembly controls the entire working program of the water heater, including water valves, gas valves, microswitches, and igniters. When installing a water heater, valves should be installed on the inlet, outlet, and gas pipes.