The capacity of a boiler is typically expressed in terms of its heat transfer rate, which is commonly measured in kilowatts (kW) or British thermal units per hour (BTU/hr). The heating surface area of a boiler alone does not provide sufficient information to determine its capacity.
The capacity of a boiler depends on various factors such as the design, fuel type, combustion efficiency, operating pressure, and temperature. To determine the capacity, you would need additional information such as the heat transfer coefficient, temperature difference, and fuel properties.
However, if you have additional data, such as the heat transfer coefficient or temperature difference, I can assist you in calculating the boiler capacity based on that information.