What must temperature pressure relief valves (TPR) be set to discharge at?

Temperature pressure relief valves (TPR) are crucial safety devices used in water heaters to prevent excessive pressure and temperature build-up, which can lead to dangerous situations. They are designed to discharge water when the water temperature exceeds a certain threshold to ensure safety.

The correct setting for TPR valves is typically at 210°F. This temperature is chosen because it is high enough to handle normal operation while still providing a safety margin to prevent the water heater from reaching a temperature that could cause damage or pose a risk. If the water temperature exceeds this limit, the TPR valve will open, allowing excess pressure or temperature to be released, thus protecting the integrity of the water heater and reducing the risk of explosion or scalding.

The other options, although they refer to high temperatures, do not meet the established safety standards that TPR valves must adhere to for the protection of the appliance and safety of occupants. Therefore, the critical temperature for discharge at 210°F fulfills the necessary safety requirements.