This boiler consists of PSI design options 30,100, and 150 with an efficiency range of 83%-85%. All steel construction and thermal shock resistance. Water surrounded cylindrical furnace for max heat transferability, with capacities of 5-86 BHP. There is optional tankless coil for indirect loads and can use gas, oil, or a combination of both. Unit works well for multiple boiler installations and offers ease of maintenance as firetubes are easily accessible.