The power of the boiler is first obtained from the nameplate or manual of the boiler, the steam boiler t/h, the hot water boiler KW or KC/h, 1t/h=690KW, 10000KC/h=11.63KW, and the power of the example 1t steam boiler is 690KW. The efficiency of the boiler is based on 90% references, and the combustion machine should be at least 690/0.9=767KW. If the actual combustor's thermal efficiency is below 90%, it will be further corrected. In addition, the maximum output of the combustion engine is not necessarily consistent with the nameplate, mainly the back pressure of the boiler furnace and the inconsistency of the combustor back pressure, which is selected and corrected according to the output curve of the combustor. This can be found at any time, and the position of the boiler is such as the altitude and the ambient temperature and boiler. The nominal difference is large, and it needs correction through the output curve of the combustion machine. Generally do not consider the environmental thermal efficiency calculated by 80% power at the maximum power of the burner, the minimum power of the combustion machine can be.