In the combustion heater, combustion air system, what prevents too much air from entering the heaters as air pressure increases?

The combustion air relief valve, or differential pressure regulator, plays a crucial role in maintaining optimal air pressure within the combustion heater. As air pressure increases, this component ensures that excessive air does not enter the heaters, which could negatively affect combustion efficiency and potentially lead to operational issues.

When the air pressure rises, the relief valve activates to manage the airflow into the combustion system, allowing only the necessary amount of air required for efficient combustion. This regulation helps maintain the desired oxygen-to-fuel ratio, ensuring that the combustion process remains stable and efficient, while also preventing potential damage to the heating system from over-pressurization.

In contrast, the other options refer to components that have different functions. The combination valve typically manages both fuel and air pressures but does not specifically regulate excess air. The air intake manifold directs airflow into the system but does not control air pressure. The excess air dump valve, while it tackles the issue of excess air, operates differently than the relief valve and does not specifically address pressure regulation for the combustion process.