Gas-fired steam boilers refer to steam boilers that use gas combustion for heating. Vertical steam boilers adopt a bottom-mounted combustion unit and a two-pass structure, ensuring complete fuel combustion, stable operation, and minimal space usage. Additionally, the flue tubes are equipped with baffle plates to slow down the exhaust gas speed and increase heat exchange, resulting in high thermal efficiency and reduced user costs. Horizontal steam boilers feature a shell-type, fully wet back, three-pass smoke tube structure. The flame burns in a slightly positive pressure within the large combustion chamber, fully extending and having a low heat load, high thermal efficiency, and effectively reducing exhaust gas temperature, leading to energy conservation and cost reduction. They are more economical to use, incorporating a corrugated furnace tube and threaded flue tube structure, which enhances the boiler's heat absorption strength while meeting the needs of heat expansion on the heat exchange surface, making them scientifically designed, reasonable, and durable.