If there is backpressure on the RP, what does the RV do?

When there is backpressure on the Reduced Pressure (RP) assembly, the Relief Valve (RV) plays a critical role in maintaining the system's integrity. In situations where backpressure could potentially lead to contamination of the potable water supply, the RV is designed to relieve excess pressure.

The RV will typically remain closed unless there is a leak at Check Valve #2 (CV #2). The purpose of having the RV close under normal backpressure conditions is to prevent any backflow from affecting the potable water side, allowing the RP assembly to function correctly. It is only when the integrity of Check Valve #2 is compromised—meaning there is a leak—that the RV will open to release water and alleviate the backpressure, ensuring the system operates safely without allowing contaminated water to flow back into the public water supply.

This mechanism is essential for preventing backflow, which could lead to significant public health risks. Understanding how the RV interacts with backpressure and Check Valve #2 underlines the importance of maintaining all components of backflow prevention assemblies in a functional condition.