Mighty Therm, Copper Tube Assembly, 2450I/2200E. LAARS Code Compliant ASME Tube Assemblies Built in accordance w/the requirements of the ASME Boiler and Pressure Vessel Code. Copper tubes and glass-lined tubs, ideal for hydronic or other closed loop, low oxygen content systems. Performs well w/normal water (7.5 to 17 grains hardness) in volume water applications.