G2 Gas Fitter Practice Exam

What must an under-fired storage water heater always have?

1. A pressure regulator

2. A temperature and pressure relief valve

3. A flow control device

4. A sediment trap

The correct answer is: A temperature and pressure relief valve

An under-fired storage water heater is required to have a temperature and pressure relief valve to ensure safe operation. This valve is crucial for preventing pressure build-up within the tank, which can occur if the water is heated beyond safe limits. The temperature and pressure relief valve serves as a safety mechanism that opens to release excess steam or hot water, thereby preventing the risk of explosion or catastrophic failure of the heater. This safety component is particularly important in under-fired systems, where heat is applied directly beneath the tank. High temperatures can quickly raise pressure levels, making the presence of a reliable relief system essential. It's a fundamental requirement in various plumbing and gas codes to ensure that water heaters function within safe operational parameters, safeguarding not just the equipment but also the surrounding environment and occupants. The other options, while potentially relevant in different contexts, do not fulfill the critical safety function that the temperature and pressure relief valve provides in this scenario.