What mechanism is crucial for the functioning of the RP assembly?

The functioning of a Reduced Pressure (RP) assembly relies on the combination of check valves and a relief valve working together effectively to prevent backflow. The check valves are essential because they create a physical barrier to reverse flow, ensuring that water can only travel in one direction through the plumbing system. This is particularly important in preventing contaminants from entering the potable water supply.

The relief valve plays a critical role in maintaining the required differential pressure within the assembly. If the pressure in the zone between the check valves drops below a certain threshold, the relief valve opens to discharge any backflow that might occur from upstream, thus preventing any potential contamination.

Without the check valves, the system would lack the necessary control over reverse flow, and without the relief valve, there would be no way to manage pressure imbalances that could lead to backflow situations. Therefore, the integration of both components is vital for the RP assembly to function correctly and provide a high level of protection against backflow. This combination ensures that the device can effectively safeguard the drinking water supply from contaminants.