This boiler consists of PSI design options which include 30, 100, & 150 with an efficiency range of 85%-87%. Construction is all steel with thermal shock proof resistance. For ultimate heat transfer, there is a water surrounded cylindrical furnace for capacities 5-86 BHP. For indirect loads there is an optional tankless coil and system fueled by gas, oil or a combination. Unit ideal for multiple boiler installations and comes with package with Aldrich Boiler Management Panel for Highest System Efficiency. Firetubes are easily accessible for ease of maintenance.