What is the setting on a T/P relief valve on a domestic 60-gallon hot water tank?

A T/P (Temperature/Pressure) relief valve on a domestic 60-gallon hot water tank is typically set to open at a pressure of 150 psi and a temperature of 210°F. This configuration is essential for safety, as it ensures that if the pressure or the temperature in the tank exceeds these levels, the valve will activate to prevent potential explosions or other hazardous situations. Maintaining the pressure at 150 psi corresponds to standard plumbing requirements for hot water systems, offering a safety cushion against excessive pressure buildup. Additionally, the temperature of 210°F acts as a safeguard, as it is the maximum temperature that standard water heaters are designed to reach before they could pose a risk of scalding or damage to the tank itself.

The other options reflect different pressure and temperature settings that are not typical for a standard domestic hot water tank, which could lead to unsafe operating conditions if they were to be used in place of the standard settings.