After obtaining the air inlet opening point value when testing a Pressure Vacuum Breaker Assembly, what must be done next?

In the procedure for testing a Pressure Vacuum Breaker Assembly, after obtaining the air inlet opening point value, the next step is to drain water from the assembly. This step is crucial because the operation of the Pressure Vacuum Breaker relies on its ability to break a vacuum and prevent back siphonage. When the water is drained, it allows for the verification of the air inlet opening function, ensuring that it will operate correctly under potential backflow conditions.

By removing the water, you are able to assess whether the assembly can effectively create a vacuum break, which is essential for its performance in protecting the water supply from contamination. This step is part of proper testing protocol to ensure that the assembly is functioning as intended. It helps to confirm that the air inlet opens at the appropriate pressure differential, reinforcing the reliability and safety of the system in preventing cross-connections.