What variable is sensed in the On-Off method of steam heating boiler burner control?

In the On-Off method of steam heating boiler burner control, boiler steam pressure is the variable that is sensed to manage the operation of the burner. This control technique operates by monitoring the steam pressure within the boiler system. When the steam pressure drops below a set threshold, the burner is activated to produce more steam and raise the pressure. Once the desired pressure is achieved, the burner turns off to prevent over-pressurization. This method is straightforward and effective for maintaining the necessary pressure levels in systems utilizing steam, making it a practical choice for many steam heating applications.

Water temperature, fuel flow rate, and combustion air pressure, while important factors in boiler operation, are not the primary variables directly controlled in the On-Off method. Instead, steam pressure serves as the key indicator for when to energize or de-energize the burner, ensuring the efficiency and safety of the boiler system.