Backflow Prevention Practice Exam

What should happen to the diaphragm of a relief valve when water pressure is correctly applied?

1. Remain closed

2. Push away from the valve seat

3. Open to allow discharge

4. Become fouled

The correct answer is: Remain closed

When water pressure is correctly applied to the diaphragm of a relief valve, the diaphragm should remain closed. This is because the primary function of a relief valve is to prevent excessive pressure buildup within a system. When the pressure is at a normal operational level, the diaphragm is held against the valve seat, ensuring that the flow of water is maintained and no discharge occurs. In normal conditions, the relief valve is designed to only open when the pressure exceeds a specified limit, allowing it to take action by releasing water to prevent potential damage from overpressure. Therefore, the diaphragm being closed under proper pressure conditions signifies that the system is functioning safely and within designed parameters. If the diaphragm were to push away from the valve seat, it would indicate that the pressure has reached a level that requires the valve to open, which is not the intended outcome when the system is operating correctly. Opening the valve to allow discharge or fouling of the diaphragm would suggest malfunction or system problems that would compromise safety.