Which type of shower valve is designed to control the volume of hot and cold water to protect against sudden temperature changes?

The correct answer is based on the function of pressure balance valves, which are specifically designed to maintain a consistent water temperature despite fluctuations in pressure within the plumbing system. These valves work by automatically adjusting the flow of hot and cold water in response to changes, such as when another fixture is used, ensuring that the user does not experience sudden temperature changes that could lead to discomfort or potential scalding.

While thermostatic mixing valves also regulate temperature, their focus is more on maintaining a specific set temperature rather than directly responding to pressure changes. Therefore, pressure balance valves are more directly related to protecting against sudden temperature changes by reacting to pressure imbalances.

Check valves primarily prevent backflow in a plumbing system and do not control water temperature or volume. Flow control valves regulate the amount of water flowing through a system but do not manage temperature or protect against sudden changes in water temperature. Thus, the design and purpose of pressure balance valves make them the appropriate choice for controlling water temperatures in showers.