What is the function of a temperature and pressure relief valve in a water heater?

The function of a temperature and pressure relief valve in a water heater is crucial for safety. It is designed to release excess temperature and pressure that may build up within the tank. Water heaters operate under a specific range of temperature and pressure; if either exceeds these limits due to factors like a malfunctioning thermostat or a blocked vent, there is a risk of an explosion. The relief valve acts as a safeguard, automatically releasing water if the temperature or pressure becomes too high, thus preventing potential hazards like tank ruptures or explosions. This feature is essential for maintaining safe operation within the system and protecting both the equipment and users.

In contrast, the other options do not correctly describe the valve's purpose. It does not increase water temperature, nor does it control the flow of water into the heater. Additionally, while filtering sediment from the water is important for water quality, that is performed by different components, not the temperature and pressure relief valve.