When testing a spill resistant vacuum breaker, to which test cock should you attach the high hose?

When testing a spill resistant vacuum breaker, the high hose should be attached to the first test cock. The reason for this is that the first test cock is specifically designed for this purpose, allowing for proper pressure measurement and ensuring that the device operates safely and effectively under testing conditions.

This setup ensures that water flows in the right manner and allows for an accurate assessment of the backflow prevention device's functioning. The other test cocks are used for different purposes in the testing process, such as measuring different points in the system or serving as drains, and thus are not intended for the primary high-pressure test required to evaluate the vacuum breaker. Using the correct test cock is crucial for obtaining reliable results during the testing process.