What happens to the relief valve if CV #2 leaks during test #3?

When testing a backflow prevention assembly, if CV #2 (which is likely a check valve) leaks during test #3, the relief valve will begin to drip. This is due to the fact that the purpose of the relief valve is to discharge water if there is backpressure or backflow occurring, which often happens when one of the check valves fails to seal properly.

In this scenario, the leak indicates that the differential pressure associated with backflow is occurring, causing the relief valve to respond by allowing water to escape as an indicator of an internal issue. The dripping is a direct sign that the backflow assembly is not working efficiently, as it is meant to prevent contaminants from entering the potable water supply. A properly functioning relief valve should not show any signs of leakage, so the presence of dripping water signifies a problem that needs addressing.

This behavior of the relief valve is critical for ensuring the system is safe and effective in preventing contamination. Understanding this function helps in diagnosing issues related to backflow prevention devices, making it an essential part of maintaining water safety standards.