Minnesota Special Engineer Boiler License Practice Exam

Which tank would you expect to find in a hot water boiler system?

1. Pressure tank

2. Safety tank

3. Expansion tank

4. Steam tank

The correct answer is: Expansion tank

In a hot water boiler system, the presence of an expansion tank is crucial for maintaining system pressure and accommodating the thermal expansion of water as it heats up. As water is heated, it expands, which increases the pressure in the system. If this pressure were to become too high, it could potentially cause damage to the boiler or associated piping. The expansion tank acts as a flexible reservoir that absorbs this extra volume of water, thereby preventing pressure build-up. It includes a bladders or diaphragm designed to separate the air from the water, allowing the tank to take in or release water as needed while maintaining a balance in pressure levels. The function of the expansion tank is essential for the safe operation of the hot water boiler system, reducing the risk of pressure-related failures. This makes it the most appropriate choice compared to other types of tanks which are either not present in a hot water system or serve different functions, such as managing steam or specific safety measures.