The operation and control of burners in combustion systems involve various modes and methods to ensure efficient and safe performance. Modes include all-or-nothing, high-low firing, and modulating, each offering different levels of control flexibility. Burners can operate with primary and secondary air functions, influencing combustion efficiency and emissions. Burners are categorized as pre-mix or nozzle-mix systems based on how air and gas are mixed. Combustion systems can be direct-fired or indirect-fired, with recuperative systems providing benefits like fuel savings. Sizing a combustion system is critical to match heat output with demand and avoid temperature fluctuations. Safety measures include flame monitors, flame arresters, and automatic fire checks to prevent accidents and ensure system integrity. Continuous monitoring and control systems regulate burner operation stages, ensuring safe and efficient combustion processes.