Gas Fitter Practice Test

What is the primary function of a pressure reducing valve?

1. Relieves system pressure in excess of the set pressure

2. Reduces the city main pressure to a safe working pressure

3. Reduces the working pressure to the city main pressure

4. Prevents hot water gravity circulation

The correct answer is: Reduces the city main pressure to a safe working pressure

The primary function of a pressure reducing valve is to reduce the city main pressure to a safe working pressure. This is essential for protecting plumbing systems and appliances that may operate at lower pressures than what is supplied directly from the city main. By lowering the incoming water or gas pressure, the valve ensures that downstream equipment operates safely and efficiently, preventing potential damage from excessive pressure. For instance, residential appliances such as gas furnaces or water heaters are designed to function optimally within specific pressure ranges. If the incoming pressure is too high, it can lead to leaks, failures, or unsafe operating conditions. The pressure reducing valve acts as a safeguard, controlling the pressure to maintain it within the parameters that are suitable for the system, thereby enhancing safety and prolonging the life of the connected appliances. The other options describe functions that do not accurately depict the primary role of a pressure reducing valve. While they pertain to pressure management in some manner, they do not align with the specific function of stepping down pressure from the city main to a usable level for systems.