What is the main function of a TPR valve in a water heater?

The main function of a Temperature and Pressure Relief (TPR) valve in a water heater is to relieve excess pressure or temperature. This is crucial for safety reasons, as water heaters can build up significant pressure due to thermal expansion or a malfunctioning thermostat. If this pressure is not properly managed, it could lead to dangerous situations, including the potential for the tank to rupture or explode.

When water in the tank heats up, it expands, increasing the pressure inside. The TPR valve is specifically designed to open when the temperature or pressure exceeds safe levels, allowing excess steam or water to escape and thus protecting the integrity of the tank and the safety of the occupants. This safety mechanism is essential in preventing catastrophic failures in water heating systems, ensuring that they function within safe operational limits.

The other options do not accurately describe the function of a TPR valve, as it does not increase pressure, maintain constant temperature, or serve any purpose related to preventing water from washing away. These misconceptions highlight the importance of clearly understanding the specific role of safety components like the TPR valve in home systems.