When performing a test on a RPZ, the #2 test cock should be:

When testing a Reduced Pressure Zone (RPZ) assembly, it is essential to flush the #2 test cock with caution. This action is necessary to ensure that there are no potential contaminants present in the system that could affect the accuracy of the reading. Flushing the test cock helps verify that the water flowing through it is clean and appropriate for safe testing.

However, care must be taken during this process to prevent a premature discharge of the relief valve. If water is introduced too quickly or forcefully, it can inadvertently trigger the relief valve, leading to erroneous test results and possibly causing water loss. Ensuring that the flushing is done gently allows for a proper assessment without disrupting the functioning of the RPZ’s relief valve.

The other choices do not align with the proper procedure for testing an RPZ. Removing the test cock completely could compromise the test setup, sealing it would not serve a purpose during testing, and covering it to allow for air pressure buildup does not facilitate the necessary flow for an accurate test.