We are offering gas & oil fired hot water boiler is a popular type, clean fuels such as natural gas, biogas, city gas, coke oven gas, blast furnace gas, lpg, heavy oil, light oil, residue oil, kerosene are available. ---efficient three-pass design, with large combustion chamber, fuels fully burn---wet-back structure, high reliability, low maintenance cost ---corrugated furnace and spirally corrugated tube structure strengthen heat efficiency---effective thermal insulating materials with a high degree of efficiency up to 95% ---equipped with imported burners. Brand of burner: germany weishaupt, italy baltur and riello, etc