What does “T and P” stand for in regards to water heaters?

In the context of water heaters, "T and P" stands for Temperature and Pressure relief valve. This component is critical for the safe operation of a water heater. The temperature and pressure relief valve serves to prevent excessive pressure buildup within the tank, which can occur due to overheating or over-pressurization of the water.

When water is heated, it expands, and if the temperature rises above a safe limit, or if the pressure becomes too high, the relief valve opens to release excess steam or water, thus preventing potential damage or catastrophic failure of the water heater. This is a vital safety feature that protects both the appliance and the surrounding environment from dangerous conditions.

The other options refer to terms that do not apply to water heater safety features and are not commonly used in plumbing terminology related to water heating systems.