Minnesota Boiler License Practice Exam

In a hot water system, what is the effect of a properly functioning expansion tank?

1. Increases boiler lifespan

2. Decreases system pressure

3. Prevents water from freezing

4. Reduces water consumption

The correct answer is: Increases boiler lifespan

A properly functioning expansion tank plays a crucial role in maintaining the longevity of a boiler. As water is heated, it expands, which can increase the pressure in the heating system. The expansion tank absorbs this excess pressure variation by allowing the water to expand into the tank, effectively preventing pressure from reaching a level that could cause stress or damage to the boiler and associated components. By controlling the pressure fluctuations within the system, the expansion tank reduces the wear and tear on the boiler, piping, and fittings. This prolongs their operational life and minimizes the chances of leaks or failures that could arise from excessive pressure. In contrast, while the expansion tank might influence various factors related to system pressure or prevent freezing indirectly, its primary and most significant function correlates with enhancing the durability and efficiency of the boiler system overall, thus supporting the idea that it increases boiler lifespan.