Hurst Boiler, 417 Square Feet Heating Surface. 4313 Steam Pounds per hour, maximum working pressure 300 psi. Serial# S417-300-1, National Board# 17575, built 2011. Includes a Power Flame Burner, model NP2-G-520, and a control panel with Compact Micro IV 5830 controller, and Siemens controllers.