The MGB Series II/MGC Series is available in nine sizes from 50 MBH to 299 MBH and is designed for chimney-vent applications. With efficiencies up to 83.9% AFUE, the latest design features a Hydrolevel FuelSmart control that monitors water temperature and delays burner start until residual heat has been transferred to the system for maximum efficiency. An integral Draft Hood and Automatic Vent Damper reduces the overall height and footprint of the boiler making it ideal for low clearance/space limited installations.