Deals with the major combustion control subsystems in boilers having steaming capabilities of 25 kg/s (200 000 lb/hr) or more. These include, but are not restricted to, furnace pressure control (balanced draft), air flow control, and fuel flow control when firing coal, gas, oil, or combinations of these. Development of boiler energy demand, all burner control, interface logic systems, and associated safety systems, including all controls connected with fluidized bed and stoker-fired combustion units are specifically excluded.