WNS series gas fired wet back boiler is fire tube three pass structure, has high thermal efficiency. This series boiler has the characteristics of compact structure, safe operation, convenient installation, low pollution and low noise, it is widely used for industry production and processing, such as textile mill, medicine industry, food & beverage industry, chemical industry, garment industry, food processing industry, and wood processing industry, moreover, it could be used for central heating in enterprise, hotel, hospital, civil architecture, etc.