CWEA Maintenance Technologist 2025 – 400 Free Practice Questions to Pass the Exam

The purpose of a thermal relief valve is to release pressure caused by thermal expansion. In various systems, particularly those involving liquids, heating can lead to an increase in pressure if the fluid expands and there is no way for that pressure to be relieved. When the temperature of the contained fluid rises, it expands, and this expansion can lead to excessive pressure build-up, which can potentially damage the system components or lead to leaks and catastrophic failures.

A thermal relief valve is designed specifically to sense this increase in pressure due to thermal expansion and open automatically to allow the excess pressure to escape. By doing so, it helps maintain system integrity and safety, ensuring that the pressure remains within safe operating limits.

In the context of the other options, increasing pressure in a system goes against the function of a thermal relief valve. Regulating flow rates is not within the operational scope of a thermal relief valve; that function is typically handled by flow control devices. Preventing water hammer is also not related to the role of a thermal relief valve; water hammer usually needs to be addressed through different mechanisms, such as air chambers or water hammer arrestors. Thus, the correct answer highlights the essential safety function of the thermal relief valve in managing pressure due to thermal effects.