Backflow Prevention Practice Exam

What condition must be met to determine the recorded value of a pressure vacuum breaker check valve?

1. Both shut-off valves are closed

2. The high-bleed valve is opened

3. The air-inlet valve opens

4. Water stops flowing from test cock 2

The correct answer is: Water stops flowing from test cock 2

To determine the recorded value of a pressure vacuum breaker check valve, it is essential that water stops flowing from test cock 2. This condition signifies that the system is under a stable state where any measurements taken will accurately reflect the operating conditions of the check valve. When water is still flowing, it can create fluctuating pressures and hydrostatic conditions that may provide misleading readings. Once flow ceases, it allows for a clear assessment of the backflow prevention device's functionality, ensuring that the pressure vacuum breaker is operating as intended. This is crucial in evaluating whether the valve is properly preventing backflow and maintaining system integrity. The other conditions do not directly contribute to an accurate assessment of the pressure vacuum breaker check valve's function. For instance, closing shut-off valves or opening the high-bleed valve may alter the dynamics of the pressure readings without confirming the valve's operational state, and the air-inlet valve opening primarily indicates the valve’s readiness to operate rather than providing a measurement for evaluation.