Minnesota Boiler License Practice Exam

An expansion tank or compression tank would be used with which type of boiler?

1. Hot water boiler

2. Steam boiler only

3. Special boiler only

4. Any type of boiler

The correct answer is: Hot water boiler

An expansion tank or compression tank is specifically designed to accommodate the thermal expansion of water as it heats up in a closed-loop hot water heating system. In hot water boilers, when water is heated, it expands, and without a means to accommodate this expansion, it can lead to excessive pressure buildup. The expansion tank absorbs the increased pressure, allowing the system to operate safely and efficiently. In contrast, steam boilers operate on a different principle. They generate steam that is then used for heating. While there are pressure and safety considerations in steam boilers, they do not typically require an expansion tank for thermal expansion like hot water boilers do. Special boilers may have specific configurations that don’t necessitate a conventional expansion tank either. Therefore, the use of an expansion tank is closely associated with hot water boilers, making it the appropriate choice.